LIBRARY 

OF  THE 

UNIVERSITY  OF  CALIFORNIA. 

Class 


A  TREATISE 

ON 

THE  DESIGN  AND  CONSTRUCTION 

OF 

MILL  BUILDINGS 

AND  OTHER  INDUSTRIAL  PLANTS 


BY 

HENRY  GRATTAX  TYRRELL,  C.  E. 
(TORONTO  UNIVERSITY) 

Author   of  Mill   Building   Construction,  1900; 

Concrete  Bridges  and  Culverts. 
History    of    Bridge   Engineering,    etc. 


CHICAGO  AXD  NEW  YOBK 

THE  MYRON  C.  CLARK  PUBLISHING  CO. 

LONDON 

E.  &  F.  N.  SPON,  LTD.,  57  HAYMABKET 
1911 


COPYRIGHT  1911 

BY 
HENRY  GRATTAN  TYRRELL. 


PREFACE 

This  book  is  the  outcome  of  a  smaller  one  entitled  "Mill  Build- 
ing Construction,"  written  in  1896  and  given  to  the  publishers  in 
1900.  These  books  are  based  on  the  personal  experience  of  the 
writer,  covering  a  period  of  twenty  years  in  designing  and  esti- 
mating buildings,  bridges  and  other  structural  work,  and  most  of 
their  contents  is  from  his  private  notes  and  records. 

A  separate  part  on  "The  Theory  of  Economic  Design"  was 
included  in  the  present  work  because  of  the  large  amount  of  capi- 
tal being  invested  in  manufacturing  plants.  A  knowledge  of  the 
possibilities  and  requirements  should  precede  the  design,  and  it  is 
only  by  the  exercise  of  such  knowledge  that  the  best  results  are 
obtained.  The  introduction  of  Part  I  has  caused  some  repetition, 
as  subjects  discussed  generally  in  this  part  are  treated  more 
fully  in  Parts  III  and  IV  on  details.  The  repetition,  however, 
seems  necessary  for  clearness,  as  the  whole  contents  of  one  part 
would  be  out  of  place  in  the  other.  This  is  particularly  the  case 
in  the  chapters  on  framing  of  northern  light  and  other  roofs. 

The  table  of  required  wall  thickness  according  to  the  building 
laws  of  different  cities,  is  subject  to  change,  but  shows  accepted 
practice.  Before  designing  buildings  for  any  of  the  cities  men- 
tioned, a  copy  of  the  latest  ordinance  should  be  consulted. 

Chapters  VI  and  VII,  on  the  comparative  cost  of  different  kinds 
of  manufacturing  buildings,  contain  estimated  costs  rather  than 
actual  ones,  for  comparisons  are  then  more  reliable,  as  external 
conditions  are  considered  uniform. 

It  was  at  first  intended  to  include  chapters  on  Graphic  Statics 
and  Calculations,  after  those  on  Loads  and  Framing,  but  these 
were  omitted  to  make  room  for  more  important  ones.  It  appears 
unnecessary,  in  a  book  on  building  construction,  to  occupy  valuable 
space  in  reviewing  mathematical  methods,  with  which  the  reader 
is  already  familiar  and  which  are  fully  treated  in  other  books. 

Chapters  XV  and  XVI  are  purposely  short,  and  consist  chiefly 
of  illustrations.  The  arrangement  of  members  for  timber  framing 

iii 

227164 


IV 


PREFACE 


(Chapter  XV)  is  similar  in  many  respects  to  that  for  steel,  which 
is  outlined  in  other  parts  of  the  book,  and  the  subject  of  Timber 
Framing  has  been  covered  by  others.  Only  a  brief  review  is  made 
in  Chapter  XVI  of  a  subject  which  has  been  completely  discussed 
in  recent  treatises,  but  the  costs,  formulae  and  other  data  given 
are  from  the  writer's  personal  records. 

Ground  floors  are  well  illustrated,  for  they  are  important,  and 
although  the  subject  has  been  much  studied,  there  is  but  little 
available  literature.  The  construction  of  upper  floors  and  espe- 
cially fireproof  ones,  is  given  less  space,  as  they  differ  little  from 
those  in  other  kinds  of  buildings.  A  hundred  pages  or  more  might 
easily  be  written  on  the  subject,  but  this  would  appear  unneces- 
sary, as  text  books  on  fireproof  building  construction  are  abundant. 

As  modern  manufacturing  plants  represent  such  large  invest- 
ments, several  chapters  are  given  to  the  preservation  of  their  ma- 
terials by  paint  arid  painting,  and  in  the  preparation  of  these 
chapters,  in  order  that  the  directions  given  might  be  the  best  and 
latest,  assistance  has  been  received  from  The  Sherwin  Williams 
Paint  Co.,  of  Cleveland  and  the  Lowe  Bros.  Paint  Co.,  of  Dayton. 

Part  V  was  prepared  especially  for  students,  estimators  and 
draftsmen,  and  to  others  it  may  appear  elementary.  The  costs 
given  are  from  my  own  notes,  and  should  be  all  the  more  valuable 
because  data  of  this  kind  are  generally  difficult  to  secure.  But- 
approximate  costs  should  be  very  carefully  used,  and  should  be  re- 
vised to  suit  the  time  and  place  in  question,  or  serious  errors  may 
result.  To  assist  in  revising  them,  a  table  is  included  giving  the 
wages  paid  to  mechanics  in  the  building  trades  in  all  parts  of 
North  America,  which  should  also  be  kept  up  to  date. 

Drawings  and  illustrations  are  freely  used,  as  they  generally 
convey  ideas  more  easily  than  text. 

Advertising  of  special  goods  or  makes  is  not  intended,  and 
where  manufacturers'  names  are  given,  it  is  only  for  the  benefit  of 
the  reader  and  not  in  any  way  to  favor  one  maker  above  another, 
excepting  as  impartial  judgment  directs. 

As  extracts  have  been  very  freely  made  by  others  from  the 
author's  writings  in  the  engineering  and  technical  journals  of 
America  and  Europe  (often  without  credit),  foot  notes  are  used, 
giving  the  date  of  the  original  articles,  and  other  notes  refer  to 
extracts  from  "Mill  Building  Construction."  Tables  I,  II,  III  and 
IV  were  supplied  by  the  Shaw  Electric  Crane  Co.  A  number  of 
illustrations  are  from  the  pages  of  Engineering  Xews,  Engineering 
Eecord,  Engineering  Magazine,  and  other  papers  and  journals,  and 


PREFACE  v 

a  few  from  Eeport  No.  V  of  The  Boston  Manufacturers'  Mutual 
Fire  Insurance  Co.  In  writing  this  book  I  have  been  greatly 
assisted,  especially  in  the  preparation  of  drawings,  by  my  wife, 
Maude  K.  Tyrrell,  who  is  a  graduate  of  the  Chicago  Art  Institute 
and  experienced  in  architecture.  H.  G.  TYRRELL. 

Evanston,  Illinois,  January,  1910. 


TABLE  OF  CONTENTS 


PAET  I. 

THEORY  OF  ECONOMIC  DESIGN. 

CHAPTER  PAGE 

I.     General  Features  and  Requirements 1 

II.     Location  and  Site 5 

Site    ', ,  10 

III.  Purpose  and  Arrangement 12 

Machinery  Arrangement    12 

Heights  and  Clearances 14 

Principal  Requirements   14 

Character  of  Buildings.     Temporary  or  Permanent 20 

Framing  and  Walls 20 

Fireproof  or  Otherwise 21 

IV.  Number  of  Stories 23 

Size  and  Weight  of  Manufactured  Products   23 

Size  and  Weight  of  Machinery    24 

Space  and  Height  for  Cranes 24 

Relative  Cost  of  Buildings  per  sq.  ft.  of  floor 24 

Cost  of  Land 28 

Relative  Convenience  of  One  or  More  Floors 29 

Lighting    31 

V.     Walls    32 

Thickness  of  Walls.    Various  Building  Laws 33 

Cost  of  Walls 36 

VI.     Cost  of  Steel  Buildings 38 

Buildings  with  Cranes.     Brick  Walls    39 

Buildings  \vith  Cranes.     Corrugated  Iron  Walls 41 

Buildings  with  Cranes.     Concrete  Walls   43 

Buildings  without  Cranes.     Concrete  Walls 44 

Buildings  without  Cranes.     Corrugated  Iron  Walls   ....  45 

Shop   Offices  or   Dwellings 52 

Summary  of  Building  Costs 55 

VII.     Comparative  Cost  of  Wood,  Steel,  and  Concrete  Buildings.  58 

Cost  of  Buildings.    Plans  A  to  G 62 

Cost  of  Buildings  60  x  100  ft 64 

Cost  of  Wood    Mill    Construction 66 

Cost  of  Reinforced  Concrete  Mill  Construction 66 

VIII.     Roof  Covering  and  Drainage 69 

Non-Condensing  Roofs  69 

Roof  Slopes    70 

Comparative  Merits    72 

Roof  Drainage  73 

Gutter  Pitches  77 

vii 


viii  TABLE  OF  CONTENTS 

CHAPTER  PAGE 

IX.  Lighting  and  Ventilating    79 

Wall  Lighting   80 

Total  Required  Lighting  Area 81 

Wall  Lighting    82 

Required  Skylight  Area 82 

Roof   Lighting   82 

Flat   Skylights   83 

Longitudinal   Monitors   83 

Cross   Monitors    85 

Box   Skylights    85 

Northern   Light   Roofs 86 

Ventilating 88 

Required    Ventilation    Area 89 

Roof  Ventilation   90 

Saw   Tooth  Ventilation 90 

Open   Roof  Ventilation .  .  91 

Individual  Metal  Ventilators 91 

Box   Skylight   Ventilators 92 

Special  Ventilators   92 

Wall  Ventilation   92 

PART  II. 

LOADS. 

X.  Static  Roof  Loads 95 

Roof  Framing    96 

Truss   Weight    Formulas 99 

Weight  of  Roof  Coverings 105 

XI.     Floor  Loads   107 

Weight  of  Building   Materials   108 

Weight  of  Merchandise 108 

XII.     Snow  and  Wind  Loads 110 

Velocity  and   Coefficients 11] 

Wind  Pressures  on  Roofs 112 

Wind  Loads   112 

XIII.  Crane  and  Miscellaneous  Loads 114 

Weight  of  Cranes 115 

Summary  of  Loads 115 

PART  III. 

FRAMING. 

XIV.  Steel  Framing   119 

Building  Frames   120 

Trusses    120 

Truss  Depth   128 

Rafters    129 

Bottom  Chords 130 

Truss  Spacing    131 

Weight  of  Trusses 132 

Monitor  Frames 132 

Girths   and    Purlins 133 

Jack  Rafters    135 

Crane  Supports   136 

Columns   142 

Floor  Framing 149 

Bracing   150 

Coal  Storage  Sheds 156 


TABLE  OF  CONTENTS 


IX 


CHAPTER  PAGE 

XV.     Wood  Framing   158 

XVI.     Concrete  Framing   168 

Adhesion  and  Bond 168 

Metal  Eeinforcement    169 

Monolithic  or  Separately  Molded  Members 169 

Type  of  Construction 170 

Floors  and  Hoof s 172 

Columns   173 

XVII.     Northern  Light  Roof  Framing,   in  Wood,   Steel  and   Con- 
crete     179 

Roof  Outlines 180 

Window  Area 180 

Gutters  and  Conductors 181 

Column   Spacing    182 

Framing 184 

Condensation    187 

Ventilation    190 

Windows 193 

Cost    194 

PART  IV. 

DETAILS  OF  CONSTRUCTION. 

XVIII.     Foundations  and  Anchorages 195 

Loads  195 

Bearing  Power  of  Soils 196 

Area  on  Soil 197 

Side  Wall  Foundations 197 

Piers 197 

Machinery  Foundations 199 

Piles     .199 

Anchors  200 

XIX.     Wall  Details  203 

Thickness   of   Walls 203 

Stone  Walls    203 

Brick  Walls    204 

Size  and  Cost  of  Brick 204 

Mortar     205 

Cost  of  Brickwork £05 

Combination  Brick  and  Concrete  Walls 207 

Reinforced  Concrete  Walls 207 

Concrete   Block   Walls 210 

Sheet  Metal  Walls 212 

Plank  Walls  213 

Wall   Anchorages    213 

XX.     Ground  Floors   218 

Kind  of  Floors 218 

Cement  Concrete  Floors 219 

Tar   Concrete  Floors 222 

Brick  Floors   224 

Asphalt  Floors 225 

Wood   Floors    227 

Wood   Block   Floors. 229 

Special  Floors    230 

XXI.     Upper  Floors   231 

Steel  Trough  Floors 231 

Flat  Plate  Floors 231 


TABLE  OF  CONTENTS 

CHAPTER  PAGE 

Metal  Arch  Floors 232 

Multiplex  Steel  Plate  Floors 234 

Triangular  Sheet  Steel  Trough 235 

Brick  Arch  Floors 236 

Reinforced   Concrete   Floors 236 

Steel  Girder  and  Timber  Floors 238 

Slow  Burning  Wood  Floors 240 

Table  of  Spruce  Plank 240 

XXII.     Eoofs— Non-Waterproof    242 

Wooden  Roofs   242 

Reinforced  Concrete  Roofs 244 

Monolithic  Concrete  Roofs  With  Forms 244 

Monolithic  Concrete  Roofs  Without  Forms 247 

Table  of  Safe  Loads,  on  Concrete  Slabs 250 

Tile  Roofs 250 

XXIII.  Roofings — Tile— Slate — Asbestos— Wood    253 

Tile  Roofing  253 

Slate  Roofing   255 

Size  and  Thickness  of  Slate 256 

Table  of  Roofing  Slate 256 

Table— Weight  of  Slate    257 

Suitable  Roof  Pitch 257 

Method  of  Laying  and  Fastening  Slate 258 

Method  of  Fastening  to  Steel  Purlins 259 

Cost  of  Slate  Roofs 261 

Reinforced  Asbestos  Corrugated  Sheathing 262 

Wood  Shingles  264 

XXIV.  Composition  Roofing  266 

Tar  and  Gravel  Roofing 266 

Asphalt  Roofing 267 

Prepared  or  Ready  Roofing 268 

Asbestos  Roofing  269 

Carey 's   Roofing    269 

Flintkote    269 

Genasco  's  Asphalt  Ready   Roofing 270 

Granite  Roofing  270 

Granite  Roofing  Specifications 270 

Monarch  Roofing   271 

Rubber  Roofing   271 

Ruberoid   Roofing    272 

XXV.     Corrugated  Iron    273 

Preservation  of  Corrugated   Iron 274 

Size  and  Weight  of  Sheets 275 

Table  of  Corrugated  Iron 276 

Strength  of  Corrugated  Iron 277 

Table  of  Loads 278 

Purlin  Spacing    279 

Roof  Pitch  for  Corrugated  Iron 279 

Laying  Corrugated  Iron  on  Roofs 279 

Laying  Corrugated  Iron  on  Walls 280 

Fastening  Corrugated  Iron 280 

Standing  Seam  Corrugated  Iron 282 

Cost  of  Corrugated  Iron 283 

Tables  of  Weight  and  Cost 283 

Asbestos  Covered  Sheets 284 

Anti-Condensation  Lining 285 

XXVI.     Sheet  Metal  Roofing  286 

Steel   Roll  Roofing 287 


TABLE  OF  CONTENTS 


CHAPTEE  PAGE 

V  Crimped  Roofing 288 

Metal  Shingles 289 

Tin  and  Terne  Plate  Roofs 289 

Standard  Specifications  for  Tin  Roofs 291 

XXVII.     Cornices    294 

Gable   Cornices    294 

Metal  Flashing   296 

Ridge  Rolls 296 

Hip  and  Valley  Flashing 296 

Corner  Capping   297 

Chimney  and  Wall  Flashing 297 

Door  and  Window  Casing 298 

XXVIII.     Gutters  and  Downspouts 299 

Gutters 299 

Hanging  Gutters   301 

Gutter  Supports    301 

Box  Gutters    303 

Roof  Gutters    303 

Combination  Roof  Gutters    304 

Valley  Gutters  304 

Downspouts    305 

XXIX.     Ventilators    308 

Individual  Metal  Ventilators 308 

Louvres    311 

Shutters 314 

XXX.     Glass    316 

Table  of  Weights 317 

Cost  of  Glass    318 

XXXI.     Skylights 319 

Bars   320 

Cost  of  Flat  Skylights 326 

Box  Skylights    327 

Tile  Skylights   .330 

Translucent  Fabric   330 

XXXII.     Windows    333 

Side  Wall  Windows 333 

Wooden  Sash   333 

Continuous  Sash 335 

Wood  Window  Frames 335 

Cost  of  Wood  Frames  and  Windows 340 

Metal  Sash  and  Windows 340 

Steel  Sash  343 

XXXIII.  Monitor  Windows    346 

Window  Opening  Mechanism 352 

XXXIV.  Doors   ' 358 

Wood  Panel  Doors 360 

Batten  Doors   361 

Table  of  Sizes 361 

Table  of  Hinges 361 

Tin  Clad  Doors   362 

Corrugated  Iron  Doors    364 

Swing  Sliding  Door    365 

Horizontal  Folding  Doors 365 

The  Ritter  Folding  Doors 368 

Special  Pier  Shed  Door 368 

Rolling  Doors    370 


Xll 


TABLE  OF  CONTENTS 


CHAPTER  PAGE 

XXXV.     Factory  Foot  Bridges 374 

Cost    375 

XXXVI.     Paint    377 

Vehicles  377 

Boiled  Linseed  Oil    378 

Pigments  or  Bases 379 

White  Lead    379 

Zinc  Oxide    380 

Bed  Lead    380 

Iron  Oxide    380 

Driers 381 

Solvents 381 

Stainers   381 

Japans  382 

Varnishes    382 

Special    Steel   Paints 383 

Prince 's    Metallic    Paint 383 

Asphalt  Paint    384 

Durable  Metal  Coating    384 

P  and  B  Paint 384 

Coal  Tar  Paint 384 

Carbonizing  Coating 385 

Graphite  Paint    385 

Cement  Coating  385 

Comparative  Merits  of  Steel   Points 386 

Paint  for  Woodwork 386 

Paint  for  Brick  or  Cement  Walls 387 

Cold  Water  Paint 387 

Whitewash    388 

Kalsomine  388 

XXXV1L     Painting    389 

Preservation  of  Materials 389 

Methods  of  Preservation 390 

Cleaning  Steelwork   390 

Pickling     390 

Sand  Blast  Cleaning  391 

Mixing  and  Applying  Paint 392 

Air    Blast    Painting 393 

Shop  Coats   394 

Paint  Table    394 

Cost  of  Painting  395 

XXXVIII.     Painting  Specifications  for  Structural  Steelwork 397 

Quality  of  Oil  and  Paint 397 

Cleaning    398 

Shop  Coat   398 

Applying  Paint   398 

Shipping    399 

Field   Painting    399 

Eepainting  Old  Steelwork 400 

Penalty    400 

PAET  V. 

ENGINEERING  AND  DRAFTING  DEPARTMENTS  OF 
STRUCTURAL  WORKS. 

XXXIX.     Engineering  Department   401 

Inquiries    401 

Organization    and    Office 402 

Office  Methods   .                                                                        .  403 


TABLE  OF  CONTENTS 


Xlll 


CHAPTER  PAGE 

Design    405 

Steel  Cage  Column  Spacing 405 

Beam  Spacing    406 

Show  Drawings   408 

XL.     Estimating  the  Quantities 410 

Approximate  Estimates 410 

Exact  Estimating    412 

Listing  Miscellaneous  Items   414 

Check  Lists 414 

Final  Classification   416 

XL1.     Estimating  the  Costs 418 

Approximate   Cost   Estimates 418 

Cost  of  Material   418 

Cost  of  Labor  and  Shop  Work 419 

Cost  of  Freight 423 

Cost  of  Estimating  and  Time  Required 424 

Tenders    425 

Preparation  of  Estimates  for  Drafting  Room 426 

XLII.     Approximate   Estimating   Prices 427 

Materials — Delivered     427 

Masonry — In  Place  427 

Piling 427 

Concrete    427 

Brickwork   428 

Carpentry  and   Mill  Work 428 

Structural  Steel  428 

Ornamental  Iron   428 

Roofing    429 

Sheet  Metal  Work 429 

Lath  and  Plaster 429 

Painting    429 

Plumbing    429 

XLIII.     The  Drafting  Office 430 

Location    431 

The  Building    431 

Welfare  Features    433 

The  File  and  Record  Room 435 

Supply  Room   436 

Inside  Arrangement   437 

Natural   Lighting    441 

Artificial  Lighting    442 

Heating  and  Ventilating 443 

Lavatories  and  Plumbing 443 

XLIV.      Organization  of  Drafting  Office 444 

Organization     447 

Subdivision  of  Labor 449 

Chief  Engineer    450 

Office  Superintendent   450 

Head  Draftsman   45] 

Squad  Foreman   451 

XLV.     Drafting  Office  Practice 454 

Preliminary  Sketches   454 

Ordering  Material  455 

Masonry   Plan    456 

Laying  Out  Work   456 

Tracing  Drawings   460 

Marking  Drawings    463 


XIV 


TABLE  OF  CONTENTS 


CHAPTER  PAGE 

Checking    464 

Corrected  Drawings    465 

Changing  Shop  Prints   465 

Listing     465 

Copying   Lists    466 

Erection  Drawings    466 

Filing  Drawings  and  Lists 467 

Copying  Drawings    467 

Photo  Eeproduction    468 

XLVI.     Cost  of  Structural  Work  Shop  Drawings 469 

XLVII.     Directions   for  Exporting  Steel  Buildings 472 

European  and  American  Practice  Compared 472 

Suitability  of  Steel  Buildings  for  Export 473 

Design  of  Export  Buildings 474 

Suggestions  for  Foreign  Purchasers 476 

Suggestions  for  Exporters    476 

Marking  Pieces   478 

Directions  to  Purchasers  in  Comparing  Plans 479 


LIST  OF  TABLES. 


PART  I. 


Crane  Clearances.  Flush  Bridge. 
Crane  Clearances.  Flush  Bridge. 
Crane  Clearances. 


PAGE 

3y2tol5tons 15 

20      to  50  tons..  16 


Standard  Bridge.      3  Ms  to  15  tons 17 


TABLE  NO. 

I. 
II. 
III. 

IV.     Crane  Clearances.     Standard  Bridge.    20      to  50  tons 18 

V.     Comparative  Cost  of  Plants 29 

VT.     Thickness   of   Walls 33 

VII.     Cost  of  Walls  per  sq.  ft 36 

VIII.     Cost  of  Steel  Buildings 55 

IX.  Comparative  Cost  of  Wood,  Steel  and  Concrete  Buildings. .  62 

X.     Cost  of  Wood  Mill  Buildings 66 

XI.     Cost  of  Concrete  Buildings 66 

XII.     Minimum    Roof    Pitches 72 

PART  II. 

XIII.  Weight  of  Roof  Coverings 105 

XIV.  Total  Weight  of  Roofs 106 

XV.     Floor  Loads 107 

XVI.     Weight   of   Materials 108 

XVII.     Table  of  Snow  Loads Ill 

XVIII.     Wind    Velocities    and    Pressures Ill 

XIX.     Wind   Coefficients    112 

XX.     Normal  Wind   Pressures 112 

XXI.     Combined  Wind  and  Snow  Loads 113 

XXII.     Electric    Crane   Loads 115 

XXIII.  Hand  Crane  Loads 116 

PART  III. 

XXIV.  Weight  of  Cast  Iron  Column  Bases 148 

XXV.     Shipping    Dimensions    156 

XXVI.     Cost  of  Reinforced  Concrete  Slabs 170 

PART  IV. 

XXVII.     Bearing  Power  of  Soils 196 

XXVLTI.     Anchor    Bolt    Dimensions 201 

XXIX.     Bearing-  Value  of  Through  Bolts 214 


TABLE  OF  CONTENTS 


XV 


TABLE  NO.  PAGE 

XXX.     Bearing  Value  of  Expansion  Bolts 216 

XXXI.     Cost  of  Wood  Floors 229 

XXXII.     Multiplex  Steel  Floors— Safe  Loads 234 

XXXIII.  Triangular   Trough   Floors 236 

XXXIV.  Thickness  and  Strength  of  Plank 240 

XXXV.     Concrete  and  Expanded  Metal  Slabs— Safe  Loads 248 

XXXVI.     Concrete  and  Dovetailed  Slabs— Safe  Loads 250 

XXXVII.     Slate  Roofing— Number  of  Slates,  Cost,  Etc 256 

XXXVIII.     Weight   of   Slate  Roofing 257 

XXXIX.     Corrugated  Asbestos  Board — Purlin  Spacing 262 

XL.     Corrugated  Asbestos  Board — Amount  Required 263 

XLI.     Weight  of  Sheet   Metal — Flat   and   Corrugated 276 

XLII.     Corrugated  Iron — Weight  per  square,  laid 276 

XLIIJ.     Corrugated  Iron — Amount    Required 276 

XLIV.     Corrugated  Iron — Dimensions    276 

XLV.     Corrugated  Iron — Contents  of  Sheets 277 

XLVI.     Safe  Load  on  Corrugated  Iron 278 

XLVII.     Purlin  Spacing  for  Corrugated  Iron 279 

XLVIII.     Clinch   Nails    281 

XLIX.     Cost  of  Corrugated   Iron 283 

L.     Weight    of   Flat   Sheets 286 

LI.     Size  of  Eave  Gutters 299 

LII.     Cost   of   Hanging   Gutters 301 

LII1.     Size  of  Gutters  and  Downspouts. 306 

L1V.     Cost  of  Galvanized  Iron  Downspouts 306 

LV.     Cost  of  Copper  Downspouts 307 

LVI.     Ventilators     309 

LVII.     Louvres 312 

LVIII.     Plate  Glass    317 

LIX.     Sash 334 

LX.     Batten  Doors   361 

LXI.     Door  Hinges    361 

LXII.     Tin  Clad  Doors   361 

LXIII.     Paint  Table  394 

PART  V. 

LXIV.     Weight   of   Steel   Buildings 411 

LXV.     Checking  List    415 

LXVI.     Cost  of  Structural  Steel 419 

LXVII.     Wages  Table   420 

LXVIII.     Cost  of  Shop  Labor   422 

LXTX.     Base   Prices 422 

LXX.     Freight  Rates    423 

LXXI.     Cost  of  Shop  Drawings 469 


PART  I 
THEORY  OF  ECONOMIC  DESIGN 


CHAPTER  I. 

GENERAL  FEATURES  AND  REQUIREMENTS. 

Mill  and  other  industrial  buildings,  in  order  to  produce  at 
minimum  cost,  must  be  carefully  planned  and  suited  to  their  indi- 
vidual needs.  There  is  a  difference  of  10  to  15  per  cent  in  the 
cost  of  labor,  resulting  from  the  convenience  of  these  buildings 
and  adaptability  to  their  use.  There  are  many  old  plants,  long 
out  of  date,  on  which  enough  money  has  been  spent  in  additions 
and  repairs,  to  construct  new  ones.  Old  buildings  which  are 
wrongly  located  or  insufficient'  to  their  needs  are  wasteful  in 
production,  and  yet  it  is  frequently  difficult  to  decide  just 
when  an  old  manufacturing  building  should  be  abandoned  and 
the  machinery  moved  into  a  new  one.  Many  companies  carrying 
on  profitable  business  are  hampered  with  a  plant  that  is  so  out  of 
date  and  so  inadequate  that  competition  with  more  recent  ones  is 
difficult.  A  complete  and  destructive  fire  is  often  the  cause  of  re- 
building modern  plants  of  suitable  strength,  containing  the  proper 
equipment  and  handling  appliances  necessary  to  meet  competition. 

Before  deciding  on  the  general  features  of  a  new  plant,  a  care- 
ful study  must  be  made  of  all  the  conditions  and  needs,  with  a 
view  not  only  to  immediate  requirements,  but  also  to  future 
extension.  Old  plants  are  generally  the  product  of  gradual  growth 
•  and  enlargement.  Starting  with  a  small  building,  others  have 
been  added  from  time  to  time,  without  regard  for  the  best  ulti- 
mate arrangement,  and  often  the  growth  of  the  plant  has  been 
unexpected.  There  are  large  iron  works  in  Pennsylvania  which 
are  producing  under  very  unfavorable  conditions,  owing  to  their 
wrong  location,  and  because  their  rapid  growth  was  unforeseen  by 
their  owners.  If  the  proprietors  of  these  industries  had  anticipated 
the  increase  of  their  business,  they  would  not  only  have  made  a 
beginning  in  a  more  favorable  location,  but  would  also  have  drawn 
a  plan  for  the  ultimate  arrangement  of  buildings,  and  developed 

1 


2  MILL  BUILDINGS 

their  plant  according  to  that  plan.  After  years  of  growth  and  the 
construction  of  numerous  buildings  filled  with  heavy  and  expensive 
machinery,  with  the  whole  site  laid  out  and  built  upon,  little  by 
little,  until  the  plant  represents  a  large  investment  of  capital, 
removal  is  then  too  costly  to  consider.  The  best  that  can  then  be 
done  is  to  carry  on  production  in  the  most  economical  way  pos- 
sible under  these  adverse  circumstances. 

There  are,  however,  many  large  but  old  plants  producing  at 
too  great  a  sacrifice,  and  these  are  being  abandoned  and  new 
buildings  erected  on  sites  with  ample  room  not  only  for  the 
present  needs  but  for  future  expansion.  In  some  cases,  where  the 
old  wooden  buildings  have  been  completely  destroyed  by  fire,  new 
ones  can  be  erected  on  the  old  location. 

Careful  study  should  be  given  to  the  requirements  of  each  indi- 
vidual building,  to  the  arrangement  of  the  different  ones  and  their 
location  in  reference  to  each  other.  They  should  be  so  placed  that 
they  may  be  economically  reached  by  one  or  more  lines  of  railroad, 
with  provision  for  receiving  and  storing  materials  and  for  storing, 
loading  and  shipping  the  products.  Buildings  should  be  so  placed 
in  reference  to  each  other  that  products  and  materials  can  be 
easily  transferred,  if  required,  from  one  building  to  another. 
The  complete  plant  should  be  so  planned  as  to  facilitate  produc- 
tion with  the  greatest  economy.  The  experience  at  other  plants 
in  manufacturing  similar  products  or  different  goods  under  simi- 
lar conditions,  will  doubtless  be  of  great  benefit,  but  it  is  unsafe 
to  lay  out  a  new  plant  exactly  like  some  other,  without  thoroughly 
examining  all  conditions  and  ascertaining  definitely  if  the  features 
are  the  best  suited  to  the  particular  industry. 

Some  modern  plants  have  buildings  connected  with  a  system 
of  tunnels  or  subways  for  pipes  and  wires,  thereby  avoiding  frequent 
trench  digging  and  taking  up  floors  to  reach  drains  or  lines  of 
water  or  steam  pipes.  The  Corn  Products  plant  at  Argo,  Illinois,, 
and  the  Sturtevant  plant  at  Hyde  Park,  Massachusetts  (Figs.  307 
and  308),  are  examples  of  those  plants  with  complete  subway 
systems.  The  subway  for  the  Sturtevant  shops  is  five  feet  in  width 
and  six  and  one-half  feet  in  height. 

A  proposed  plan  for  the  arrangement  of  a  set  of  shops  for  a 
complete  plant  is  shown  in  Fig.  1.  The  buildings  are  arranged 
with  their  longitudinal  axes  radiating  from  a  center,  and  are  con- 
nected by  two  circular  lines  of  railway,  an  inner  and  an  outer 
one.  At  the  center  of  the  plant  is  located  the  executive  building, 
containing  the  general  offices,  and  the  shop  offices  for  the  various 


FEATURES  AND  EEQUIEEMENTS  3 

buildings  are  located  in  the  shops  at  the  ends  adjoining  the  execu- 
tive building.  With  this  arrangement,  the  management  is  in 
close  touch  with  the  foremen  of  the  shops  and  can  secure  personal 
consultations  on  short  notice,  which  is  difficult  where  the  shop 
offices  are  scattered  over  a  large  area.  While  the  plan  has  some 


Gates 


Street    Railway 
Fig.  1. 

points  of  merit,  there  are  other  features,  especially  that  of  track 
service,  which  cannot  be  recommended. 

A  more  practical  plan,  laid  out  on  parallel  lines,  is  shown 
in  Fig.  2.  The  executive  office  occupies  the  center  of  the  plot, 
with  shops  at  either  side,  and  a  power  house  in  the  rear  adjoin- 
ing the  shipping  yards.  The  plant  is  served  by  both  rail  and 


4  MILL  BUILDINGS 

water,  while  street  cars  pass  in  front  and  a  branch  line  joins  the 
city  railway  system  with  the  storage  and  shipping  yards.  At  both 
sides  of  the  plant  there  is  additional  space  for  future  expansion  if 
required.  The  ground  in  front  adjoining  the  street  is  laid  out  in 
grass  plots  with  ponds  and  shrubbery,  and  contains  two  buildings 
devoted  to  welfare  features,  with  a  dining-room  on  one  side  and  a 
library  and  rest  room  on  the  other.  A  complete  tunnel  system 


Railway 
Fig.   2. 

connects  the  buildings  with  the  power  House,  and  foot  bridges  join 
the  shops  at  each  story.  In  the  plaza  directly  in  front  of  the 
executive  building  is  a  fountain,  and  between  the  shops  are  beds 
of  flowers,  shrubbery  and  grass.  These  plans  are  suggestions  for 
a  convenient,  symmetrical  and  artistic  arrangement,  and  would  be 
modified  to  suit  particular  demands. 

Figs.  3,  4  and  5  show  plants  actually  built,  the  first  being  in 
Germany  and  the  others  in  America. 


CHAPTER  II. 

LOCATION  AND  SITE. 

Most  old  plants  are  not  economically  located.  They  have 
grown  from  small  beginnings,  and  were  built  in  the  vicinity  of 
their  owners'  residence,  without  reference  to  the  principles  of 
economic  location  and  production.  Their  location  is,  in  fact,  an 
accident.  Little  by  little  these  plants  have  developed,  until  large 
manufacturing  industries  have  resulted,  which  are  not  only  remote 
from  their  source  of  supplies,  but  often  have  poor  shipping  facili- 
ties and  insufficient  labor.  There  is,  in  one  of  the  Eastern  States, 
a  large  structural  iron  works  on  a  branch  railroad  several 
miles  from  the  main  line,  which  was  started  twenty  years 
ago  as  a  sheet  metal  shop  with  a  single  wooden  building.  It 
was  owned  and  operated  by  a  resident  of  the  adjacent  village.  A 
change  of  management  was  made,  and  in  ten  years  the  little  plant 
developed  into  a  large  and  prosperous  one,  manufacturing  all  kinds 
of  structural  iron  work  in  addition  to  its  original  sheet  metal 
products.  The  nearest  labor  market  was  ten  to  fifteen  miles  dis- 
tant, and  raw  materials  were  brought  largely  from  Pittsburg. 
After  a  dozen  or  more  buildings  had  been  erected,  it  was  decided 
to  remove  the  entire  works  to  the  vicinity  of  Pittsburg,  near  the 
source  of  supplies  and  the  best  market  for  structural  labor.  At 
the  old  location,  dividends  were  being  wasted  in  useless  freight 
charges,  and  the  market  area  for  manufactured  products  was 
limited  in  comparison  to  the  corresponding  area  when  near  the 
source  of  raw  materials. 

In  selecting  an  economical  location  for  a  manufacturing  plant, 
the  following  are  the  chief  considerations : 

(1)  The  amount  of  ground  required  for  yards  and  buildings. 

(2)  Value   and   availability  of  land   for  present  needs   and 
extension. 

(3)  The  amount  of  labor  in  the  vicinity. 

(4)  Proximity  to  source  of  power  and  cost  of  same. 

(5)  Proximity  to  source  of  raw  materials. 

(6)  Distance  from  residence  of  owners. 

5 


MILL  BUILDINGS 


Fig.  3. 


LOCATION  AND  KITE  7 

(7)  Presence  of  shipping  facilities,  with  rail  and  water  com- 
petition if  possible. 

Some  kinds  of  manufacturing  plants,  such  as  car  shops,  struc- 
tural mill  and  iron  works,  require  a  large  area  of  land,  not 
only  for  the  storage  of  materials  and  products,  but  also  for  spread- 
ing out  their  one-story  buildings.  The  contents  of  these  shops  are 
usually  too  large  and  heavy  to  handle  on  upper  floors,  and  single 
stories  are  therefore  needed.  The  amount  of  land  required  for 
such  work  generally  necessitates  too  great  an  investment  in  the 


Fig.  4. 


land  itself,  to  warrant  other  than  a  suburban  or  country  location. 
There  are,  however,  occasional  plants  still  existing  in  the  large 
cities,  occupying  so  extensive  a  ground  area  that  the  sale  of 
their  city  property  would  more  than  pay  the  cost  of  land  and 
new  buildings  in  the  country,,  where  values  are  low  and  taxes 
correspondingly  small.  The  importance  of  the  proper  location  is 
therefore  evident.  A  suburb  is  often  most  desirable,  because,  while 
land  values  and  taxes  are  comparatively  low,  it  is  still  in  close 
proximity  to  a  source  of  supplies  and  labor.  In  making  a  choice, 


g  MILL  BUILDINGS 

therefore,  between  a  city  and  its  suburb,  the  selection  will  depend 
largely  on  the  comparative  land  values  and  the  presence  of  labor. 

Land  that  might  cost  from  $5  to  $25  per  square  foot  in  the  city 
could  probably  be  secured  in  a  suburb  for  10  to  25  cents  per  square 
foot.  If  a  suburb  be  selected,  it  is  probable  that  an  office  in  the 
adjoining  city  may  be  desirable  or  necessary,  and  the  additional 
expense  of  maintaining  the  office  must  be  counted  in  the  com- 
parison. A  disadvantage  of  a  suburban  location  is  that  the  manu- 
facturing company  may  have  to  invest  capital  in  homes  for  work- 
men. This  was  necessary  in  connection  with  the  Pennsylvania 
Steel  Company's  new  plant,  the  American  Bridge  Company's  works 
at  Ambridge,  and  the  Associated  Industries  of  Sault  Ste.  Marie, 
Ontario.  Wnen  a  force  of  workmen  has  been  secured!  for  the 
suburban  plant  and  the  men  with  their  families  are  settled  in 
their  homes,  the  manufacturing  company  will  then  have  much 
better  employees  in  their  shops  than  would  be  secured  from  the 
migrating  class  usually  found  in  large  cities.  Eural  workmen,  living 
at  home  with  their  families,  are  usually  more  reliable  and  better 
able  to  do  a  full  day's  work,  and  they  can  generally  be  depended 
upon  for  extra  work  or  emergencies.  On  the  other  hand,  in  times 
of  commercial  and  financial  depression,  when  manufactories  are 
doing  but  little  work,  these  companies  must  exercise  paternalism 
with  their  employees,  often  at  great  expense.  After  work- 
men have  gone  through  one  period  of  depression  and  have 
received  the  support  of  their  employers,  they  will  generally  be 
more  loyal  to  their  companies  and  will  have  less  desire  to  seek 
employment  elsewhere.  Such  experiences  tend  to  establish  confi- 
dence between  employers  and'  employees.  If  the  suburban  work- 
men were  dismissed  or  temporarily  laid  off  when  the  amount  of 
work  in  the  shops  was  small,  it  would  probably  be  difficult  to 
find  other  men  on  short  notice  when  business  revived.  In  large 
cities,  these  conditions  are  reversed.  Labor  can  usually  be  obtained 
at  a  lower  price,  laid  off  when  not  needed,  and  new  men  employed 
when  required. 

When  a  manufacturing  establishment  has  been  located  in  the 
country  or  suburb,  and  a  corps  of  workmen  secured  and  settled 
in  their  homes,  if  the  company  then  wishes  to  remove  the 
plant  to  an  urban  site,  it  may  be  difficult  or  impossible  to  per- 
suade the  well-trained  rural  employees  to  move  with  them.  The 
better  class  of  skilled  labor  usually  prefers  to  remain  at  home 
rather  than  to  shift  about  from  place  to  place. 

It  is  much  easier  to  finance  a  new  enterprise  for  a  city  loca- 


LOCATION  AND  SITE 


tion  than  one  in  the  country,  because  the  buildings  in  a  city  can 
be  used  for  other  purposes  if  the  enterprise  fails.     The  suburb 


Fig.  5. 


or  rural  site  affords  a  better  opportunity  for  expansion,  better 
light  and  purer  air  'for  its  operators  and  owners,  with  correspond- 
ingly better  results.  Considered  merely  as  a  machine.,  there  is  no 


10  MILL  BUILDINGS 

longer  any  doubt  that  a  man  can  and  will  do  better  work  and 
more  of  it,  when  surrounded  by  the  ordinary  comforts  and  working 
in  good  light  and  pure  air,  than  under  reversed  conditions. 

When  the  value  of  manufactures  is  large  in  comparison  to  the 
place  occupied  in  making  them,  particularly  where  work  can  be 
economically  conducted  on  several  floors,  the  city  may  be  more 
convenient  and  advisable. 

In  selecting  the  genera,!  location  of  a  plant  with  reference  to 
the  part  of  the  country  in  which  it  shall  be  placed,  it  should  be 
remembered  that  in  any  department  of  industry,  labor  is  more 
easily  found  in  districts  where  there  are  other  manufactures  of  the 
same  kind.  For  instance,  in  starting  a  new  furniture  factory, 
the  most  abundant  source  of  labor  would  be  found  in  such  a  city 
as  Grand  Eapids,  while  for  a  new  hardware  industry,  the  best  labor 
market  would  doubtless  be  in  some  of  the  manufacturing  cities  of 
Connecticut.  Skilled  labor  for  the  manufacture  of  shoes  would 
be  most  easily  found  at  such  a  place  as  Lynn  or  Brockton,  Massa- 
chusetts, and  labor  for  structural  steel  work  at  such  cities  as 
Harrisburg  or  Pittsburg.  As  stated  before,  the  availability  of  labor 
and  the  nearness  to  the  source  of  raw  material  will  usually  govern. 

SITE. 

Having  decided  upon  the  district  in  which  the  plant  shall  be 
located,  and  whether  it  shall  be  in  a  city  or  in  one  of  its  suburbs, 
the  actual  site  for  the  buildings  must  then  be  chosen.  It  should, 
if  possible,  be  accessible  both  by  rail  and  water  and  by  competing 
lines  of  railway,  in  order  to  secure  the  lowest  freight  rates.  There 
should  be  ample  opportunity  for  spur  tracks  or  sidings,  and  the 
site  should  be  high  enough  above  the  neighboring  waterways  or 
valleys  so  it  can  be  thoroughly  drained.  If  located  away  from  a 
city,  it  should  have  convenient  trolley  connections  to  the  adjoin- 
ing town,  and  be  reasonably  near  the  source  of  supplies  for  both 
shops,  and  the  workmen  and  their  families. 

The  ground  on  which  the  buildings  are  to  be  placed  should  be 
graded  with  a  slope  of  about  six  inches  per  100  feet  in  the  direc- 
tion in  which  materials  and  products  will  pass  in  going  through 
the  works.  With  a  slight  grade,  it  is  easier  for  the  workmen  to 
move  small  service  cars,  loaded  with  material,  as  products  pass 
through  the  various  buildings  in  course  of  manufacture. 

The  possibility  of  finding  near  at  hand  the  various  kinds  of 
building  material  needed,  may  have  weight  in  choosing  a  site, 


LOCATION  AND  SITE  H 

Occasionally  land  is  available  where  sand  and  stone  are  abundant 
without  hauling,  and  expense  of  building  is  thus  reduced. 

A  survey  of  the  ground  must  be  made,  the  lot  lines  and  other 
external  limitations  established,  streets  laid  out,  sewers,  water  and 
gas  pipes  shown  and  all  buildings  and  sidings  indicated  in  their 
proposed  places.  Borings  should  be  made,  if  necessary,  to  deter- 
mine the  strata  and  bearing  power  of  the  soil. 


CHAPTER  III. 

PURPOSE  AND  ARRANGEMENT. 

The  term  "mill  building"  includes  a  large  variety  of  manu- 
facturing plants,  such  as  rolling  mills,  car  shops,  storehouses, 
sugar  mills,  car  sheds,  foundries,  machine  shops,  forge  shops,  etc. 
The  particular  nature  of  a  building  will  in  each  case  determine  its 
principal  features.  Each  kind  will  have  its  own  special  require- 
ments, and  for  this  reason  no  rules  can  be  given  for  the  form  or  size. 

MACHINES Y  AKKANGEMENT. 

In  undertaking  the  design  of  a  manufacturing  building,  the 
designer  must  prepare  or  secure  outline  drawings  showing  the 
space  required  for  the  contents.  Either  the  building  should  be 
designed  in  consultation  with  the  mechanical  engineer,  or  if  this 
is  not  convenient,  the  building  engineer  must  obtain  from  the 
mechanical  engineer  such  complete  data  in  reference  to  the  ar- 
rangement of  the  machinery,  the  space  that  it  will  occupy,  and 
the  loads  it  will  cause  on  any  or  all  parts  of  the  building  frame, 
that  he  may  proceed  to  develop  his  design  with  confidence  and 
accuracy.  The  mechanical  engineer  or  those  familiar  with  the 
processes  of  manufacture  in  the  particular  line  of  work  in  hand 
should  first  arrange  all  machinery,  preferably  regardless  of  the 
building,  so  manufacturing  can  be  carried  on  at  least  cost.  The  vari- 
ous machines  should  be  so  placed  that  material  in  course  of  manu- 
facture will  pass  in  one  direction  consecutively  from  one  machine 
or  operation  to  another,  until  finally  completed  and  ready  for  ship- 
ment. Each  machine  must  have  sufficient  space  about  it  for  han- 
dling and  possibly  turning  material,  space  for  workmen  and  some 
for  storing  small  excess  material  or  products. 

A  mill  building  is  in  reality  a  part  of  the  machinery,  and 
should  be  designed  as  such  rather  than  as  a  work  of  architecture. 
Utility  must  have  preference  over  appearance,  but  both  may  usually 
receive  proper  attention.  The  presence  of  cranes  and  other  appli- 
ances for  handling  materials  makes  the  building  a  part  of  the 
mechanical  equipment.  The  building  must,  however,  be  sub- 
servient to  its  use,  and  its  form  and  shape  be  made  to  prop- 
erly surround  and  house  the  machinery  and  contents.  The  loca- 

12 


PUEPOSE  AND  ARRANGEMENT 


13 


tion  of  certain  machines  may  make  it  necessary  to  omit  columns, 
and  to  provide  especially  large  bays  in  side  walls  for  admitting 
and  removing  large  machines.  It  is  imperative  that  the  machinery 
be  exactly  located  before  plans  for  the  building  itself  are  drawn, 
to  avoid  the  possibility  of  columns  or  other  framing  being  placed 


Fig.   6. 

in  a  position  where  machines  must  stand.  The  building  must, 
in  fact,  be  made  to  fit  the  mill.  (Fig.  6.)  The  form,  length, 
height  and  width  will  then  depend  upon  the  contents.  If  ground 
is  unlimited,  there  is  no  difficulty  in  placing  the  machines  to  the 
best  possible  advantage  and  surrounding  and  covering  them  suita- 
bly, but  if  the  size  or  form  of  the  lots  is  limited,  the  building  plan 
must  necessarily  conform  to  its  outline. 


14 


MILL  BUILDINGS 


HEIGHTS  AND  CLEAEANCES. 

The  equipment  and  contents  of  a  building  must  be  examined 
both  as  to  plan  and  elevation,  to  ascertain  the  amount  of  space 
required  above  and  around  them.  The  weight  and  maximum 
dimensions  of  all  materials  and  products  must  be  accurately  known 
and  the  general  style  of  cranes  and  other  handling  or  conveying 
appliances  selected  before  the  height  beneath  the  trusses  can  be 
determined.  There  must  also  be  ample  space  allowed  for  heat- 
ing and  ventilating  ducts,  belts,  hoists,  shafting  and  any  other 
contents.  Generally,  high  buildings  are  lighter  than  lower  ones, 
and  it  is  easier  to  keep  leather  belts  tight  when  they  are  long, 
than  when  in  a  lower  building.  Fig.  7  shows  the  method  of  deter- 


Fig.  7. 


Fig.  8. 


mining  the  required  height  beneath  the  trusses.  On  the  floor 
is  first  drawn  the  maximum  height  of  the  machines  or  fixtures 
over  which  products  or  materials  must  be  lifted  or  conveyed.  The 
maximum  outline  for  any  pieces  requiring  crane  service  is  drawn 
above  this  and  over  this  is  shown  the  crane  hook  with  trolley  and 
crane  bridge  above  it.  In  drawing  these  heights,  clearances  should 
be  allowed  in  each  case  and  the  sketch,  if  to  scale,  will  show  accu- 
rately the  total  height  required  below  the  trusses. 

For  further  determining  the  clearances  required  for  traveling 
cranes,  the  following  four  tables  are  given,  which  show  not  only 
the  necessary  clearances,  but  give  also  the  maximum  wheel  load 
on  the  crane  girders  and  the  total  net  weight  of  the  crane  in 
pounds.  A  method  of  securing  clearance  and  space  for  opening 
Bwing  sash  on  the  monitor  side  is  shown  in  Fig.  8,  in  which  the 
sash  when  open  will  cause  no  obstruction  to  the  crane. 

PRINCIPAL  REQUIREMENTS. 

A  building  that  will  enable  men  and  machinery  to  produce 
results  in  the  most  direct  and  cheapest  way,  is  the  best. 

If  there  are  several  buildings  in  the  plant,  they  must  be  so 


PURPOSE  AND  ARRANGEMENT 


15 


TABLE    I. 


OUTSIDE    DIMENSIONS    OF    3%    TO    15    TON    STANDARD    ELECTRIC    TRAVELING    CRANES. 

Table  is  for  hoist  of  about  30  ft.     Higher  hoist  may  increase  wheel  base. 
Dimension  R  may  be  reduced  if  necessary. 

FLUSH  BRIDGE. 


Capacity  in  Tons 

A 

R 

J 

K 

L 

M 

N 

0 

P 

Maximum 
Load  on 
each  wheel 

Total  net 
Weight  of 
Crane 

06 
'S 

a-t~ 

s| 

3£ 
In. 

"1 

=i 

«» 
gs 

§w: 

*d 

•"", 

Urn 

Trol. 

E 

In. 

Bract 

hrut 
ting 
Trav. 

G 

In. 

Ft. 

In. 

FUn 

Ft.  In 

Ft.In 

Ft.In 

FUn 

Ft.In 

Ft.In 

Lbs. 

Lbs. 

3% 

sy2 
sy2 
3y2 

3% 

3y2 

30 
40 
50 
60 
70 
80 

7% 

I* 

8 
9 
9 

3  6 
3  6 
3  8 
3  8 
3  11 
4  1 

4  2 
4  2 
4  2 
4  2 
4  2 
4  2 

n 

1  7 
1  8 

1  8 

1    6 

1    7 
1    7 
1    8 
1    8 

6  3 
6  3 
6  3 
6  3 
6  3 

7  1 
7  1 
7  1 
7  1 
7  1 
7  1 

8    8|     9,300 
8  10    10,200 
9    6|  11,300 
10    01  12,600 
11    8    14,300 
13    4|  16,000 

16,700 
19,200 
23,300 
27,700 
33,600 
39,900 

15 

15 
18 
18 
21 
21 

3b 
35 
35 
40 
40 
45 

7       7 
7       7 
9       8 
9       8 
11      10 
11      10 

5 
5 
5 
5 
5 
5 

30 
40 
50 
60 
70 
80 

I* 

8 
9 
9 
9 

3  11 
4  2 
4  2 
4  4 
4  6 
4  9 

4  8 
4  8 
4  8 
4  8 
4  8 
4  8 

2  2 
2  1 
2  1 
2  0 
2  0 
2  0 

1    9 
1  10 
1  10 
1  11 
1  11 
1  11 

6  3 
6  3 
6  3 
6  3 
6  3 
6  3 

7  1 
7  1 
7  1 
7  1 
7  1 
7  1 

10    1 
10    1 
10    4 
10  10 
11    8 
13    4 

11,600 
12,800 
14,100 
15,500 
17,100 
18,900 

19,500 
22,400 
26,200 
31,300 
37,300 
43,400 

15 

18 
18 
21 
21 
21 

40 
40 
40 
45 
45 
45 

5       9 
5      11 
5      11 
5      13 
5      13 
5      13 

ft 
ft 

7y2 
7y2 

30 
40 
50 
60 
70 
80 

81/4 

8* 

9 
10 
10 

4  5 
4  5 
4  7 
4  9 
4  11 
5  1 

5  0 
5  0 
5  0 
5  0 
5  0 
5  0 

11 

2  1 
2  1 
2  2 
2  2 

2    0 
2    0 
2    1 
2    1 
2    2 
2    2 

6  3 
6  3 
6  3 
6  3 
6  3 
6  3 

7  1 
7  1 
7  1 
7  1 
7  1 
7  1 

10    7 
10    8 
10    3 
10    5 
11    8 
13    4 

14,900 
16,200 
17,600 
19,100 

20,800 
22,700 

22,300 
24,900 
28,800 
34,100 
40,700 
47,000 

21 
21 
21 
21 
24 
24 

40 
45 
45 
45 
50 
50 

5 
5 
5 
5 

7 

7 

8 
8 
10 
10 
12 
12 

10 
10 
10 
10 
10 
10 

30 
40 
50 
60 
70 
80 

8J4 

9% 
9% 
10 
10 
10 

4  7 
4  10 
4  10 
5  0 
5  2 
5  4 

5  8 
5  R 
5  8 
5  8 
5  8 
5  8 

2  5 
2  4 
2  4 
2  3 
2  3 
2  3 

2    2 
2    1 
2    1 
2    3 
2    3 
2    3 

6  3 
6  3 
6  3 
6  3 
6  3 
6  3 

7  1 
7  1 
7  1 
7  1 
7  1 
7  1 

10    7 
10    9 
10  10 
10  11 
11    8 
13    4 

18.500 
19,800 
21,200 
22,700 
24,500 
26,800 

23,500 
28,400 
32.400 
37,800 
43,100 
52,100 

21 
24 
24 
24 
24 
24 

45 
50 
50 
50 
50 
55 

5 
5 
5 
5 
5 
5 

10 
10 
10 
12 
12 
12 

15 
15 
15 
15 
15 
15 

30 
40 
50 
60 
70 
80 

ft 

10% 
10% 

10  y2 
10  y2 

5  0 
5  0 
5  2 
5  4 
5  6 
5  8 

6  6 
6  6 
6  6 
6  6 
6  6 
6  6 

2  7 
2  7 
2  6 
2  6 
2  6 
2  6 

3    0 
3    0 
2  11 
2  11 
2  11 
2  11 

6  3 
6  3 
6  3 
6  3 
6  3 
6  3 

7  1 
7  1 
7  1 
7  1 
7  1 
7  1 

11    8 
11    8 
11    7 
11    6 
11    8 
13    4 

25,000 
26,500 
28,100 
29,800 
31,800 
34,300 

29,600 
33,900 
38,600 
44,000 
51,200 
59.800 

24 
24 
24 
24 
24 
24 

50 
55 
55 
60 
60 
65 

6 
6 
6 
6 
6 
6 

9 
9 
9 
9 
9 
9 

16 


MILL  BUILDINGS 


TABLE   II. 

OUTSIDE    DIMENSIONS    OF    20    TO    50     TON     STANDARD    ELECTRIC    TRAVELING    CRANES. 

FLUSH  BRIDGE. 


Capacity  in  Tons 

A 

Ft, 

R 

J 

K 

L 

M 

N 

o 

P 

Maximum 
Load  on 
each  wheel 

Total  Net 
Weight  of 
Crane 

•! 

?! 

&£ 

In. 

M"S 

*<>> 

^% 

J! 

§H 
*d 

Max.  Brace 
without 

limiting 
Trol.  Trav. 

E 

In. 

G 

In. 

In. 

Ft.In 

Ft.In 

Ft.In 

FUn 

FUn 

FUn 

FUn 

Lbs. 

Lbs. 

20 
20 
20 
20 
20 
20 

30 
40 
50 
60 

70 
80 

9i/2 

101/2 

10% 
10% 
10% 
10% 

5  4 
5  6 
5  8 
5  10 
6  1 
6  3 

8  8 
8  8 
8  8 
8  8 
8  8 
8  8 

2    8 
2    7 
2    7 
2    7 
2    7 
2    7 

3    0 
2  11 
2  11 
2  11 
211 
2  11 

6  3 
6  3 
6  3 
6  3 
6  3 
6  3 

7    1 
7    1 
7    1 
7    1 
7    1 
7    1 

11    9 
11    7 
11    9 
11    4 
11    8 
13    4 

31,000 
32,700 
34,600 
37,000 
39.700 
42,800 

32,800 
37,600 
45,000 
50,700 
58,200 
70,600 

24 
24 
24 
24 
24 
24 

60 
60 
65 
65 
70 
70 

10 
10 
10 
10 
10 
10 

10 
10 
10 
10 
10 
10 

25 
25 
25 
25 
25 
25 

40 
50 
55 
60 

70 
80 

10% 
10% 
10% 

11% 
111,4 
11% 

5  11 
6  1 
6  2 
6  4 
6  6 
6  8 

9  1 
9  1 
9  1 
9  1 
9  1 
9  1 

2    8 
2    8 
2    8 
2    9 
2    9 
2    9 

3    1 
3    1 
3    1 
3    1 
3    1 
3    1 

6  3 
6  3 
6  3 
6  3 
6  3 
6  3 

n 

7    1 
7    1 

7    1 
7    1 

12    2 
11  11 
12    1 
12    5 
12    2 
13    4 

39,300 
41,800 
43,100 
44,500 
47,500 
50,800 

43,400 
49,500 
54,200 
58,700 
69,100 
79,900 

24 

24 
24 
27 
27 
27 

70 
70 
70 
70 
75 
75 

11 
11 
11 

12 

12 
12 

10 
10 
10 

11 
11 

11 

30 
30 
30 
30 
30 

40 
50 
60 

70 
80 

111/4 

11% 

121/4 

12% 
12% 

6  3 
6  5 

6  7 
6  10 

7  0 

10  0 
10  0 
10  0 
10  0 
10  0 

2  11 
2  11 
3    0 
3    0 
3    0 

3    2 
3    2 
3    1 
3    1 
3    1 

6  3 
6  3 
6  3 
6  3 
6  3 

7    1 
7    1 
7    1 
7    1 
7    1 

13    0 
12  10 
13    3 
13    1 
13    4 

46,200 
48,800 
51,700 
55,000 
58,800 

49,500 
56,800 
66,600 
77,300 
90,700 

27 
27 
30 
30 
30 

75 
75 
80 
80 
85 

13 
13 
15 
15 
15 

12 
12 
12 
12 
12 

40 
40 
40 
40 
40 

40 
50 
60 

70 
80 

13% 
13% 
13% 
13% 
13% 

6  10 
7  0 
7  2 

7  4 
7  7 

11  6 
11  6 
11  6 
11  6 
11  6 

3    2 
3    2 
3    2 

3    2 
3    2 

3    2 
3    2 
3    2 
3    2 
3    2 

6  3 
6  3 
6  3 
6  3 
6  3 

7    1 
7    1 
7    1 
7    1 
7    1 

13    7 
13    5 
13    2 
12    5 
13    4 

60,100 
63,400 
67,000 
71.000 
75,600 

64,200 
72,800 
84,300 
96,800 
112,900 

30 
30 
30 
30 
30 

85 
85 
90 
90 
90 

18 
18 
18 
18 
18 

15 
15 
15 
15 
15 

50 
50 
50 
50 
50 
50 

40 
50 
55 
60 

70 
80 

13% 
13% 
13% 
11% 
11% 
11% 

7  6 
7  8 
7  8 

12  11 
12  11 
12  11 
12  11 
12  11 
12  11 

3    5 
3    5 
3    5 

3    7 
3    7 
3    7 

6  3 
6  3 
6  3 
6  3 
6  3 
6  3 

7    1 
7    1 
7    1 
7    1 
7    1 
7    1 

13    0 
12    8 
12  10 

74,000 
77,600 
79,800 
41,200 
43,300 
45,900 

76,100 
85,700 
92,200 
98,500 
112,700 
131,200 

30 
30 
30 
24 
24 
24 

90 
95 
95 
70 
70 
75 

19 
19 
19 
19 
19 
19 

16 
16 
16 
16 
16 
16 



PUEPOSE  AND  ARRANGEMENT 


TABLE   III. 


OUTSIDE    DIMENSIONS    OF    3%     TO    15-TON    STANDARD    ELECTRIC    TRAVELING    CRANES. 

Table  is  for  hoist  of  about  30  feet.     Higher  hoist  may  increase  wheel  base. 
Dimensions  R  and  J  can  be  reduced  if  necessary. 

STANDARD  BRIDGE. 


Capacity  in  Tons. 

A 

R 

J 

K 

L 

M 

N 

o 

P 

Maximum 
Load  on 
each  wheel 

Total  Net 
Weight  of 
Crane 

g*  Dia.  Bridge 
P  1  Wheel 

Runway  Rail  A.  S. 
C.  E.,  Lbs.  per  yard  II 

Max 
wi 

lim 
Trol 

E 

In, 

Brace 

bout 
iting 
Trav. 

G 

In. 

Ft. 

In. 

Ft.In 

FUn 

Ft.In 

Ft.In 

FUn 

Ft.In 

FUn 

Lbs. 

Lbs. 

3V2 
3i/2 

ft 
ft 

30 
40 
50 
60 

70 
80 

7% 

I% 

8 

ft 

4    7 
4    8 
4  11 
5    0 
5    2 
5    4 

4  2 
4  2 
4  2 
4  2 
4  2 
4  2 

1    6 
1    6 

1    7 
1    7 
1    7 
1    7 

1  6 
1  6 

1  7 
1  7 
1  7 

1  7 

6    3 
6    3 
6    3 
6    3 
6    3 
6    3 

6    3 
6    3 
6    1 
6    1 
6    0 
6    0 

7    3 
7    4 
8    4 
10    0 
11    8 
13    4 

9,300 
10,200 
11,300 
12,600 
tt-,300 
16,000 

16,700 
19,200 
23,300 
27,700 
33,600 
39,900 

lb 
15 
18 
18 
21 
21 

3b 
35 
35 
40 
40 
45 

7 
7 
9 
9 
9 
9 

7    ' 
7 
8 
8 
8 
8 

5 
5 
5 
5 
5 
5 

30 
40 
50 
60 
70 
80 

I* 

8 
8% 

8V4 

8% 

5    1 
5    4 
5    5 
5    8 
5    9 
5  11 

4  8 
4  8 
4  8 
4  8 
4  8 
4  8 

2    2 
2    1 

2    1 
2    1 
2    1 
2    1 

1  9 
1  10 
1  10 
1  10 
1  10 
1  10 

6    3 
6    3 
6    3 
6    3 

6    3 
6    3 

6    3 
6    1 
6    1 
6    0 
6    0 
6    0 

7    8 
7  11 
8    4 
10    0 
11    8 
13    4 

11,600 
12,800 
14,100 
15,500 
17,100 
18,900 

19,500 
22,400 
26,200 
31,300 
37,300 
43,400 

15 
18 
18 
21 
21 
21 

40 
40 
40 
45 
45 
45 

5 
5 
5 
5 
5 
5 

9 
11 
11 
11 
11 
11 

7% 

7V<> 
7% 

30 
40 
50 
60 
70 
80 

8V4 

8% 

sy4 

81/4 

9^4 
9% 

5    8 
5    9 
5  10 
5  11 
6    3 
6    5 

5  0 
5  0 
5  0 
5  0 
5  0 
5  0 

2    2 
2    2 
2    2 
2    2 
2    1 
2    1 

2  0 
2  0 
2  0 
2  0 
2  0 
2  0 

6    3 
6    3 
6    3 
6    3 
6    3 
.   6    3 

6    0 
6    0 
6    0 
6    0 
5  10 
5  10 

8    4 
8    5 
8    6 
10    0 
11    8 
13    4 

14,900 
16,200 
17,600 
19,100 
20,800 
22-,700 

22,300 
24,900 
28,800 
34,100 
40,700 
47,000 

21 
21 
21 
21 
24 
24 

40 
45 
45 
45 
50 
50 

5 
5 
5 
5 
5 
5 

8 
8 
8 
8 
9 
9 

10 
10 
10 
10 
10 
10 

30 
40 
50 
60 

70 
80 

8V4 
9% 
9% 
9% 
91/4 
9y4 

5  11 
6    3 
6    4 
6    5 
6    6 
6    8 

5  8 
5  8 
5  8 
5  8 
5  8 
5  8 

2    5 
•    2    4 
2    4 
2    4 
2    4 
2    4 

2  2 

2  1 
2  1 
2  1 
2  1 
2  1 

6    3 
6    3 
6    3 
6    3 
6    3 
6    3 

6    0 
5  10 
5  10 
5  10 
5  10 
5  10 

8    4 
8    7 
8    9 
10    0 
11    8 
13    4 

18,500 
19,800 
21,200 
22,700 
24,500 
26,800 

23,500 
28,400 
32,400 
37,800 
43,100 
52,100 

21 
24 
24 
24 
24 
24 

4b 
50 
50 
50 
50 
50 

b 
5 
5 
5 
5 
5 

10 
10 
10 
10 
10 
10 

15 
15 
15 
15 
15 
15 

30 
40 
50 
60 
70 
80 

9% 

9% 
9% 
9V2 
10% 
10% 

6    4 
6    6 
6    7 
6    8 
6  10 
7    1 

6  6 
6  6 
6  6 
6  6 
6  6 
6  6 

2    7 
2    7 
2    7 
2    7 
2    6 
2    6 

3  0 
3  0 
3  0 
3  0 
2  11 
2  11 

6    3 
6    3 
6    3 
6    3 
6    3 
6    3 

5  10 
5  10 
5  10 
5  10 
5    9 
5    9 

9    6 
9    6 
9    4 
10    0 
11    8 
13    4 

25,0001 
26,500 
28,100 
29,800 
31,8001 
34,300| 

29,600 
33,900 

US.  (500 
44,000 
51,200 
59,800 

24 
24 
24 
24 
24 
24 

50 
55 
55 
60 
60 
65 

6 
6 
6 
6 
6 
6 

9 
9 
9 
9 
9 
9 

18 


MILL  BUILDINGS 


TABLE    IV. 

OUTSIDE    DIMENSIONS    OF    20    TO    50-TON     STANDARD    ELECTRIC    TRAVELING    CRANES. 
STANDARD  BRIDGE. 


Capacity  in  Tons. 

A 

R 

J 

K 

L 

M 

N 

0 

P 

Pi 

Maximum 
Load  on 
each  wheel 

1° 

«•«• 

•aSs 

m 

Dia.  Bridge! 
Wheel 

«S 

<jt» 

ss 
«« 

F. 

§» 
*d 

Max. 
wit 
lim 
Trol. 

E 

In. 

Brace 
bout 

*!n6 
Trav. 

G 

In. 

Ft. 

In. 

Ft.In 

FUn 

Ft.In 

Ft.In 

FUn 

Ft.In 

Ft.In 

FUn 

Lbs. 

Lbs. 

In. 

20 
20 
20 
20 
20 
20 

30 
40 
50 
60 
70 
80 

9y2 
10  y2 

10% 
10% 

10% 
10% 

6  10 

7    0 
7    2 
7    3 
7    5 

7    7 

8  8 
8  8 
8  8 
8  8 
8  8 
8  8 

2  8 
2  7 
2  7 
2  7 
2  7 
2  7 

3  0 
2  11 
2  11 
2  11 
2  11 
2  11 

6    3 
6 
6 
6 
6 
6 

5    9 
5    9 
5    9 
5    9 
5    9 
5    9 

9    2 
9    2 
9    2 
10    0 
11    8 
13    4 

31,000 
32,700 
34,600 
37,000 
39,700 
42,800 

32,800 
37,600 
45,000 
50,700 
58,200 
70,600 

24 
24 
24 
24 
24 
24 

60 
60 
65 
65 
70 
70 

10 
10 
10 
10 
10' 
10 

10 
10 
10 
10 
10 
10 

25 
25 
25 
25 
25 
25 

40 
50 
55 
60 
70 
80 

10% 
10% 
10% 

11% 
11% 
11  ¥4 

7    4 
7    6 
7    7 
7    9 
7  11 
8    2 

9  1 
9  1 
9  1 
9  1 
9  1 
9  1 

2  8 
2  8 
2  8 
2  9 
2  9 
2  9 

3  1 
3  1 
3  1 
3  1 
3  1 
3  1 

6 
6 
6 
6 
6 
6    3 

5    9 
5    9 
5    9 
5-  7 
5    7 
5    7 

9    7 
9    9 
9  11 
10  10 
11    8 
13    4 

39,300 
41,800 
43,100 
44,500 
47,500 
50,800 

43,400 
49,500 
54,200 
58,700 
69,100 
79,900 

24 
24 
24 

27 
27 
27 

70 

70 
70 
70 
75 
75 

11 
11 
11 

12 
12 
12 

10 
10 
10 

11 
11 
11 

30 
30 
30 
30 
30 

40 
50 
60 
70 
80 

11% 
11% 

12% 
12% 
12% 

7    9 
711 
8    3 
8    5 
8    8 

10  0 
10  0 
10  0 
10  0 
10  0 

2  11 
2  11 
3  0 
3  0 
3  0 

3  2 
3  2 
3  1 
3  1 
3  1 

6    3 
6    3 
6    3 
6    3 
6    3 

5    7 
5    7 
5    5 
5    5 
5    5 

10    4 
10    6 
11    2 
11    8 
13    4 

46,200 
48,800 
51,700 
55,000 
58,800 

49,500 
56,800 
66,600 
77,300 
90,700 

2V 
27 
30 
30 
30 

75 
75 

80 
80 

85 

13 
13 
15 
15 
15 

12 
12 
12 

12 
12 

40 
40 
40 
40 
40 

40 
50 
60 
70 
80 

13% 
13% 
13% 
13% 
13% 

8    6 
8    8 
8  10 
9    0 
9    3 

11  6 
11  6 
11  6 
11  6 
11  6 

3  2 
3  2 
3  2 
3  2 
3  2 

3  2 
3  2 
3  2 
3  2 
3  2 

6    3 
6    3 
6    3 
6    3 
6    3 

5    5 
5    5 
5    5 
5    5 
5    5 

11    4 
11    6 
11  10 
12    0 
13    4 

60,100 
63,400 
67,000 
71,000 
75,600 

64,200 
72,800 
84,300 
96,800 
112,900 

30 
30 
30 
30 
30 

85 
85 
90 
90 
90 

18 
18 
18 
18 
18 

15 
15 
15 
15 
15 

50 
50 
50 
50 
50 
50 

40 
50 
55 

60 
70 

80 

13% 
13% 
13% 
11% 
11% 
11% 

9    2 
9    4 
9    5 
9    4 
9    9 
10    0 

12  11 
12  11 
12  11 
12  11 
12  11 
12  11 

3  5 
3  5 
3  5 

3  7 
3  7 
3  7 

3  7 
3  7 
3  7 
3  9 
3  9 
3  9 

6    3 
6    3 
6    3 
6    3 
6    3 
6    3 

5    5 
5    5 
5    5 
5    7 
5    5 
5    5 

11    4 
11    6 
11    8 
11    0 
11    8 
13    2 

"s'io 

4  0 
5  1 

74,000 
77,600 
79,800 
41,200 
43,300 
45,900 

76,100 
85,700 
92,200 
98,500 
112,700 
131,200 

30 
30 
30 
24 
24 
24 

90 
95 
95 
70 
70 
75 

19 
19 
19 
19 
19 
19 

16 
16 
16 
16 
16 
16 

PURPOSE  AND  ARRANGEMENT  19 

located  that  material  and  products  may  be  conveniently  transferred 
from  one  building  to  another.  The  primary  requisites  are  as 
follows : 

(1)  One  or  more  working  floors  of  ample  area. 

(2)  Buildings  large  enough  for  men,  machinery  and  equip- 
ment. 

(3)  Protection  of  the  contents  from  the  weather  and  of  tools 
and  materials  from  theft. 

(4)  Avoidance  of  useless  travel. 

(5)  Buildings  well  braced  and  rigid,  and  able  to  safely  sus- 
tain their  maximum  loads. 

(6)  Sufficient  space  for  machinery  and  goods  in  process  of 
manufacture. 

(?)     All  floor  space,  as  far  as  possible,  open  to  view. 

(8)  The  trusses  and  other  framing  strong  enough,  if  neces- 
sary, to  carry  shafting  or  trolleys  on  the  bottom  chord. 

(9)  Departments  producing  noise,  smoke,  gas,  odors  or  fire, 
partitioned  from  the  rest  of  the  shop,  but  partitions  used  only 
where  necessary,  as  they  occupy  valuable  space,  obstruct  light  and 
make  hiding  places  for  workmen. 

(10)  Separate  rooms  for  drafting  or  shop  offices. 

(11)  Clothes  presses  or  lockers  for  the  safekeeping  of  em- 
ployees' clothing  and  other  effects. 

(12)  Sanitary  toilets  and  wash  rooms. 

(13)  Buildings   properly  heated,   lighted   and   ventilated,   as 
required. 

(14)  Cranes  or  other  lifting,  handling  or  conveying  appli- 
ances wherever  needed. 

(15)  Space    for    receiving,    storing,    loading    and    shipping 
materials. 

(16)  Provision  for  admitting  or  removing  the  largest  pieces 
of  machinery  that  will  ever  be  placed  in  the  building. 

(17)  Buildings  designed  with  a  view  to  future  extension. 

(18)  Separate  floor  space  for  both  light  and  heavy  manu- 
facturing if  needed. 

(19)  Provision  for  fire  extinction. 

The  essentials,  therefore,  are  strength,  simplicity,  utility  and 
economy.  Buildings  are  for  assisting  in  production  and  are  sec- 
ondary to  their  contents.  Poor  light,  a  chilly  atmosphere  and 
impure  air  impair  man's  activity,  and  it  is  for  the  best  interests 
of  all  that  human  producers  be  surrounded  with  such  comforts 
and  conveniences  as  will  permit  them  to  render  their  best  services. 


20  MILL  BUILDINGS 

CHAEACTEE  OF  BUILDINGS— TEMPORARY  OE  PEEMANENT. 

Whether  the  buildings  shall  be  temporary  or  permanent,  fire- 
proof or  otherwise,  will  depend  upon  conditions,  some  of  which 
are  as  follows: 

The  amount  of  money  immediately  available  may  not  be  suffi- 
cient to  pay  for  more  than  a  temporary  building,  or  there  may  be 
insufficient  time  for  the  erection  of  permanent  structures.  Fre- 
quently valuable  contracts  are  secured  which  must  be  completed 
in  a  specified  time,  requiring  additional  machinery  and  -buildings. 
In  both  of  the  above  instances  it  may  be  economical  to  use  tem- 
porary buildings  which  can  be  erected  quickly,  rather  than  to  wait 
a  longer  time  for  more  substantial  ones.  The  site  may  be  a  tem- 
porary one,  to  be  used  for  a  short  time  only,  the  buildings  then  to 
be  removed  and  abandoned,  as  occurs  during  the  construction 
of  large  public  works  where  local  shops  may  be  needed.  During 
the  erection  of  the  Forth  bridge  in  Scotland,  a  temporary  bridge 
and  structural  plant  was  built  close  to  the  bridge  site,  in  which 
much  of  the  fabrication  was  executed. 

When  a  manufacturing  venture  is  started,  the  ultimate  outcome 
of  which  is  uncertain,  the  investors  may  at  first  prefer  temporary 
buildings,  and  even  then  only  such  as  are  absolutely  needed,  until 
such  time  as  the  success  of  the  business  is  assured.  These  and 
numerous  other  reasons  may  arise  to  determine  their  character. 

FRAMING  AND  WALLS. 

The  framing  for  industrial  buildings  will  consist  of  either 
wood,  steel  or  reinforced  concrete,  inclosed  with  walls  of  stone, 
brick,  concrete,  reinforced  concrete,  sheet  metal  or  wood.  The 
roof  trusses  or  beams  will  rest  either  on  solid  walls  or  on  columns 
with  sides  of  plank,  corrugated  iron  or  light  masonry  curtain 
walls.  The  merits  and  comparative  costs  of  various  kinds  of 
walls  are  discussed  in  detail  under  another  heading,  but  a  few 
general  features  of  wall  construction  are  given  here. 

If  the  purpose  of  the  building  is  such  that  it  will  require  heat- 
ing, the  walls  and  covering  must  then  have  sufficient  thickness 
and  be  otherwise  designed  to  act  as  nonconductors.  Brick  walls, 
either  solid  or  hollow,  are  satisfactory  for  heated  buildings,  but 
walls  of  either  stone  or  concrete,  unless  hollow,  are  liable  to  cause 
excessive  condensation  on  the  inner  side.  For  this  reason,  hollow 
concrete  blocks  are  sometimes  used,  or  double  concrete  slabs  from 
two  to  three  inches  thick,  each  slab  being  reinforced  with  a  sheet 
of  wire  mesh  or  expanded  metal.  Buildings  where  heat  is  not 


PURPOSE  AND  ARRANGEMENT  21 

required  may  have  exterior  walls  of  sheet  metal  or  corrugated 
iron  laid  either  on  girths  or  over  plank  sheathing,  or  the  sheath- 
ing may  be  waterproofed  with  shingles  or  clapboard.  The  nature 
of  the  walls  will  also  to  some  extent  depend  upon  the  amount 
of  light  required  from  the  sides. 

As  a  general  rule,  steel  framing  is  preferable  for  trusses  and 
large  girders,  which  are  subjected  to  impact,  as,  for  example,  shop 
girders  carrying  traveling  cranes.  Columns,  all  ordinary  floor 
framing,  girders  of  medium  dimensions  carrying  static  loads,  and 
wall  lintels,  are  generally  more  economical  and  satisfactory  when 
made  of  reinforced  concrete.  This  kind  of  composite  construction 
is  well  illustrated  by  the  shops  at  El  Paso,  Texas,  for  the  Atchi- 
son,  Topeka  and  Santa  Fe  Eailroad  Company. 

FIREPROOF  OR  OTHERWISE. 

There  need  be  no  difficulty  in  making  a  selection  between 
wood,  steel  or  reinforced  concrete  framing.  For  light  loads,  wood 
is  satisfactory  for  columns,  but  not  for  trusses  and  other  framing 
where  difficulty  is  experienced  in  making  joints  of  sufficient 
strength..  Light  wooden  framing  is  easily  and  quickly  destroyed 
by  fire,  and  is  therefore  unsatisfactory  for  permanent  work.  It 
has  been  frequently  proven  that  heavy  \vood  columns  resist  fire 
much  better  than  unprotected  steel  or  iron.  The  metal  columns 
fail  by  bending  at  a  high  temperature,  while  wooden  ones  are  con- 
sumed slowly. 

Steel  columns  inclosed  in  masonry  walls  are  often  unsatisfac- 
tory and  not  economical  because  they  must  be  surrounded  by  suffi- 
cient brick  or  other  fireproofing  to  make  a  pier  which  would  be 
strong  enough  without  the  steel.  This  kind  of  pier  and  column 
construction  being  less  economical,  reinforced  concrete  columns 
are  coming  extensively  into  use.  The  reinforcing  steel  is  in  the 
form  of  light  angles  with  just  enough  compressive  strength  to 
temporarily  support  the  roof  or  other  framing  during  erection, 
and  after  the  various  parts  of  the  metal  frame  are  riveted  or 
bolted  together,  the  concrete  of  the  column  is  then  placed.  This 
type  is  economical  because  the  entire  area  of  both  steel  and  con- 
crete is  considered  in  resisting  the  compressive  stresses.  Unpro- 
tected steel  framing  is  lacking  in  fireproof  qualities,  and  yet  to 
enclose  the  interior  columns  or  other  framing  with  fireproofing 
would  make  the  cost  prohibitive.  As  a  result,  few,  if  any,  manu- 
facturing buildings  have  their  steel  framing  enclosed. 

The  fire  at  the  Lewiston   (Maine)   car  barns,  the  interior  of 


22  MILL  BUILDINGS 

which  was  made  of  steel,  was  so  destructive  that  in  seven  minutes 
after  the  beginning  of  the  fire  the  roof  fell.  A  similar  case 
occurred  October  25,  1904,  at  the  car  barns  of  the  Forest  Hill 
Station  of  the  Boston  Elevated  Railway,  at  West  Roxbury,  Massa- 
chusetts. In  this  case  the  steel  trusses  and  other  framing  failed 
fifteen  minutes  after  the  beginning  of  the  fire.  There  are  numer- 
ous cases  on  record  where  fires  have  taken  place  in  buildings  of 
wood  mill  construction,  and  while  the  buildings  were  ultimately 
destroyed,  the  total  collapse  did  not  happen  until  the  cross  sec- 
tional area  of  the  framing  was  seriously  reduced.  This  destructive 
process  usually  occupies  half  an  hour  or  more,  and  therefore  gives 
a  greater  time  for  the  contents  of  a  building  to  be  removed.  With 
exposed  steel  framing,  a  collapse  occurs  more  quickly  under  exces- 
sive heat.  In  order  to  give  greater  protection  to  the  contents  of 
car  sheds,  it  has  been  proposed  to  divide  them  by  numerous  fire- 
proof longitudinal  walls,  separating  the  various  tracks;  but  these 
walls  would  evidently  be  too  great  an  inconvenience  to  warrant 
their  use.  It  has  been  further  suggested  that  the  floors  of  car 
sheds  containing  cars  valued  at  from  $2,000  to  $3,000  apiece 
shall  be  laid  with  a  sufficient  grade  so  that  in  case  of  fire  the  cars 
would  run  out  by  force  of  gravity.  The  chief  reason  for  not 
making  buildings  of  fireproof  material  is  the  extra  first  cost  of 
their  construction.  When  the  valuable  contents  of  a  building  and 
the  extra  expense  for  insurance  are  considered,  it  is  a  doubtful 
policy  to  carry  on  any  manufacturing  business  in  buildings  that 
are  not  fireproof  or  to  use  such  buildings  for  the  storage  of  mate- 
rial or  products. 

A  table  of  approximate  costs  for  buildings  of  various  types  of 
construction  is  given  in  Chapter  VII. 


CHAPTER  IV. 

NUMBER  OF  STORIES. 

One  of  the  first  questions  that  will  present  itself  in  planning  a 
manufacturing  plant  is  in  reference  to  the  height  of  buildings  or 
number  of  stories  in  them.  A  decision  must  be  made  as  to 
whether  work  will  be  done  all  on  one  floor  or  on  several.  In  order 
to  intelligently  and  economically  decide  the  question,  it  is  necessary 
to  consider — 

(1)  Size  and  weight  of  manufactured  products. 

(2)  Size  and  weight  of  machinery. 

(3)  Space  and  height  required  for  traveling  cranes. 

(4)  Relative  cost  of  buildings  per  square  foot  of  floor  sur- 
face for  one  or  more  stories. 

(5)  Cost  of  land. 

(6)  Relative  convenience  and  economy  of  manufacturing  and 
handling  goods  on  one  floor  or  on  several  floors. 

(7)  Lighting. 

(1)  When  the  manufactured  products  and  the  raw  material 
used  in  a  building  are  excessively  heavy,  there  will  then  be  little 
or  no  choice  about  the  number  of  floors,  for  all  heavy  pieces  and 
assembled  products  must  stand  upon  the  ground.  Their  size  and 
weight  would  prohibit  handling  them  on  floors  above  the  ground. 
In  this  class  may  be  mentioned  car  and  locomotive  shops,  bridge 
and  structural  plants,  foundries  for  heavy  castings,  etc.  There 
will  be  certain  parts,  before  the  products  are  assembled,  that  are 
not  too  heavy  for  upper  floors,  but  the  general  assembled  product, 
with  the  need  for  numerous  lines  of  tracks,  will  require  a  single- 
story  building  with  perhaps  galleries  for  some  of  the  lighter  parts. 
Even  in  these  heavy  plants,  much  light  work  can  be  done  on 
upper  floors,  and  for  this  space  it  is  simply  a  choice  in  compara- 
tive cost  between  building  a  larger  ground  floor  or  making  one  or 
more  upper  floors  of  the  needed  area. 

The  relative  cost  of  galleries  or  upper  floors  compared  to 
ground-floor  space  is  considered  more  fully  in  a  later  paragraph. 
The  comparison  is  plainly  illustrated  in  Fig.  9,  which  shows  a 
building  of  common  form  with  high  center  bay  and  lower  side 

23 


24:  MILL  BUILDINGS 

ones.  If  it  is  found  that  there  is  a  sufficient  amount  of  light 
work  and  machinery  for  the  gallery  floor  shown  at  F,  the  choice 
will  depend  largely,  if  not  entirely,  on  the  cost  of  this  gallery 
floor  compared  with  the  combined  cost  of  the  roof  E,  added  to 
the  ground  floor  G,  and  the  additional  land  L.  If  the  cost  of  F 

is  less  than  E  plus  G  plus  L,  the 

gallery  floor  will  then  be  the  more 

economical. 

(2)     The   second   consideration 

in   choosing  between  one   or   more 


Fig>  9i  stories   is   the   size   and   weight   of 

shop    machinery.       In    car    shops, 

bridge  plants,  etc.,  heavy  machinery,  such  as  punches,  planers, 
steam  hammers,  etc.,  requiring  heavy  and  elaborate  foundations, 
must  necessarily  be  upon  the  ground. 

(3)  The  space  and  height  required  for  cranes  will  depend 
upon   the   size   of   the   manufactured   products.      The   method   of 
determining  this  height  and  clearance  has  already  been  described 
in   Chapter   III,   under   the  head   of   "Heights   and    Clearances." 
Where  high  settings   are  required   for  the  cranes,   it   is   imprac- 
ticable to  use  more  than  a  single  floor  in  the  crane  bay,  for  the 
products,   being   assembled   under   the   runway,   must   necessarily 
rest  on  a  solid  floor.     The  upper  view  of  Fig.  10  shows  a  cross 
section  of  the  erecting  shop  for  the  Worthington  Hydraulic  Works 
at  Harrison,  New  Jersey,  built  in  the  year  1904.    The  two  interior 
lines  of  columns  are  spaced  60  feet  apart  on  centers,  and  the  clear 
head  room  in  the  center  bay  is   72  feet.      The  crane  clearance, 
therefore,  in  this  and  other  similar  cases  is  the  governing  factor 
in  deciding  on  a  single  floor  only,  in  the  erecting  shop.     There  is 
sufficient  light  machine  work  to  occupy  the  three  gallery  floors 
on  either  side  of  the  erecting  floor.     The  lower  view  of  Fig.  10 
is  the  machine  shop  for  the  same  company.     Fig.  11  is  a  cross 
section  of  the  machine  shop  for  the  General  Electric  Company  at 
Schenectady,  New  York.     One-half  of  the  building  shown  is  made 
in  three  stories   with  two  floors  for   light  machinery  above  the 
ground.     In  the  other  half,  the  clearance  required  for  cranes  in 
the  erection  aisle  prohibits  the  use  of  any  intermediate  floors,  and 
the  entire  space  of  62  feet  beneath  the  trusses  is  therefore  left 
open. 

(4)  Fig.  12  shows  the  relative  cost  per  square  foot  of  floor 
area  for  ordinary  mill  construction  factory  buildings  in  widths  up 
to  125  feet  and  heights  from  one  to  five  stories.     The  costs  given 


NUMBER  OF  STORIES 


25 


are  for  wood  construction  in  floors  and  roofs,  inclosed  in  brick 
walls.  Buildings  of  steel  and  reinforced  concrete  have  a  different 
cost  per  square  foot  of  floor,  but  the  relative  cost  for  one  story 
or  many  will  be  about  the  same.  In  the  following  table,  the  cost 
of  a  one-story  building  is  taken  as  unity,  and  the  cost  of  a  build- 
ing, for  width  of  50  feet,  from  two  to  five  stories  is  given  in  terms 
thereof. 


High      Erecting      Shop 


2O  and  30-Ton 
Crane,  Pun  way.  ^ 


•  —  ere"- mf- sow 4 


Machine     Shop. 
Fig.  10. 


RELATIVE    COST    OF    MANUFACTURING    BUILDINGS    50    FEET    IN    WIDTH    AND    OF 

VARIOUS    HEIGHTS,    BUILT    OF   EITHER   WOOD,    STEEL   OR 

REINFORCED    CONCRETE. 

Cost  per  sq.  ft.  of  total  floor  area — one  story $1.00 

Cost  per  sq.  ft.  of  total  floor  area — two  story 92 

Cost  per  sq.  ft.  of  total  floor  area— three  story.  . , 87 

Cost  per  sq.  ft.  of  total  floor  area— four  story 86 

Cost  per  sq.  ft.  of  total  floor  area — five  story 85 


MILL  BUILDINGS 


NUMBEE  OF  STOEIES  37 

It  appears,  therefore,  that  buildings  of  one  and  two  stories 
cost  more  than  buildings  of  three,  four  and  five  stories,  the  last 
being  15  per  cent  less  per  square  foot  of  gross  floor  area  than  when 
all  floor  space  is  on  the  ground.  For  light  products,  it  is  therefore 
economical  to  make  manufacturing  buildings  not  less  than  three 
stories  in  height,  for  not  only  is  the  building  itself  less  expensive, 
but  it  also  occupies  smaller  ground  space.  The  only  probable 
reason  that  might  cause  the  owner  of  a  building  for  light  manu- 


The  Influence  of  Width  and 
Height  on  the  Cosf  of  a  Building 
of  Ordinary  Mill  Construction 


$1.30 


1.10 


o 

9 

1.00  fc 
o 

u- 

.90  8 

% 


.80 


«  .70 


25  50  75  100 

Width     of     Building     in     Feet. 

Fig.   12. 


1*5 


.60 


facturing  purposes  to  select  one  floor  in  preference  to  three  or 
more  would  be  the  relative  convenience  and  economy  of  carrying 
on  the  work  on  a  single  floor.  Records  of  certain  factories  show 
that  the  cost  of  labor  is  from  5  to  10  per  cent  less  when  work  is 
all  done  on  a  single  floor  rather  than  on  several  floors.  It  must, 
therefore,  be  ascertained  if  the  saving  in  the  pay  roll  from  better 
lighting  and  other  conditions  in  light  manufacturing  buildings 
will  be  enough  to  pay  interest  on  the  cost  of  extra  land  and  the 
increased  cost  of  the  one-story  building.  One  of  the  principal 
reasons  for  one-story  buildings  costing  so  much  more  per  square 


23  MILL  BUILDINGS 

foot  of  floor  area  than  those  of  two  or  more  stories  is  because  of 
the  extra  cost  of  skylights,  which  are  not  required  in  multi-story 
buildings. 

(5)  It  is  assumed  that  the  possibility  of  using  expensive  city 
land  as  a  site  for  a  manufacturing  plant  is  under  consideration, 
and  it  is  desired  to  ascertain  the  amount  of  ground  and  correspond- 
ing investment  that  is  economical. 

One-story  buildings,  whether  the  products  and  machinery  be 
light  or  heavy,  can  generally  be  used;  whereas  buildings  of  two 
or  more  stories  are  suitable  only  when  a  large  part  of  the  work  is 
light  manufacturing. 

Therefore,  before  making  any  comparison  of  the  relative  cost 
between  buildings  of  one  story  or  more,  it  must  be  definitely 
known  for  what  proportion  of  the  entire  floor  surface,  solid  ground 
will  be  required.  If  a  large  part  of  the  work  can  as  well  be  done 
on  upper  floors  as  on  the  ground,  it  is  then  in  order  to  add  the 
number  of  stories  to  this  ground  floor  area  to  equal  the  total 
required,  and  which  is  the  most  economical,  when  the  cost  of  land, 
building  and  production  is  considered.  Fig.  13  shows  a  building 


Fig.  13. 

with  five  tiers  of  floors  and  a  one-story  building  with  the  same 
total  floor  area.  The  total  cost  of  securing  any  required  floor 
space,  either  one  floor  or  more,  may  be  found  by  first  computing 
the  relative  costs  of  the  buildings  and  to  these  costs  adding  the 
value  of  the  land  on  which  they  stand.  The  sum  of  these  will  be 
the  net  investment.  It  can  then  be  decided  what  saving  in  produc- 
tion in  a  low  building  will  pay  the  interest  on  the  additional 
investment. 

For  the  purpose  of  illustrating  these  operations,  the  following 
example  is  given :  A  manufacturing  company  requires  a  new 
building  with  a  total  floor  space  of  36,000  square  feet,  and  it  is 
desired  to  find  if  it  will  be  more  economical  to  have  this  all  on 
one  floor  or  on  several  floors.  It  is  assumed,  for  comparison,  that 
the  one-story  building  will  cost  90  cents  per  square  foot  for  the 
building  only.  The  percentages  given  on  page  25  show  that 


NUMBER  OF  STORIES  29 

buildings  of  two,  three,  four  and  five  stories  cost,  respectively,  92, 
87,  86  and  85  per  cent  of  the  cost  of  a  one-story  building.  The 
cost  per  square  foot  of  floor  surface  for  buildings  of  from  one 
to  five  stories  will  therefore  vary  from  90  to  76  cents,  and  the 
total  cost  for  36,000  square  feet  will  vary  from  $32,400  to  $27,360. 
The  ground  area  required  varies  from  36,000  square  feet  for  a  one- 
story  to  7,200  square  feet  for  a  five-story  building,  and  this  land, 
figured  at  an  assumed  value  of  $5  per  square  foot,  would  cost 
from  $180,000  to  $36,000,  making  the  total  investment  for  the 
land  and  buildings  vary  from  $212,400  for  the  one-story  to  $63,360 
for  the  five-story  building.  These  figures  are  all  clearly  shown  in 
Table  V.  The  difference  in  cost  of  land  and  buildings  between 
the  one  and  the  five  story  building  is  therefore  about  $150,000. 
The  annual  interest  on  $150,000  at  6  per  cent,  is  $9,000.  There- 
fore, to  decide  whether  a  one-story  building  is  more  economical 
than  a  five-story  building,  it  is  simply  necessary  to  determine 
whether,  the  yearly  saving  in  production  will  be  equal  to  or  greater 
than  $9,000.  If  the  saving  is  more  than  this  amount,  the  one- 
story  building  is  then  economical,  even  though  the  building  and 
land  on  which  it  stands  represent  a  greater  cost. 

It  has  already  been  stated  that  cost  records  from  one-story 
shops  show  that  the  saving  in  production  is  from  5  to  10  per 
cent.  Therefore,  to  make  a  total  saving  of  $9,000,  the  annual 
production  cost  for  the  assumed  shop  must  be  from  $90,000  to 
$180,000. 

TABLE  V. 

COMPARATIVE   COSTS   OF  ASSUMED   PLANTS,  INCLUDING   BOTH  LAND  AND  BUILD- 
INGS  FOR   HEIGHTS   VARYING   FROM    ONE   TO   FIVE   STORIES. 

Number  of  Stories —      One.  Two.  Three.          Four.  Five. 

Percentage  cost.  .  .          100.00  92.00  87.00  86.00  85.00 

Cost  per  sq.  ft.  of 

floor  $  .90  $  .83  $  .78  $  .77  $  .76 

Total  cost  of  build- 
ing    $32,400.00  $29,880.00  $28,080.00  $27,720.00  $27,360.00 

Lot  area  required, 

sq.  ft 36,000.00  18>000.00  12,000.00  9,000.00  7,200.00 

Cost  of  lot  at  $5 

per  sq.  ft $180,000.00  $90,000.00  $60,000.00  $45,000.00  $36,000.00 

Total  cost  of  land 
and  building $212,400.00  $119,880.00  $88,080.00  $72,720.00  $63,360.00 

(6)  The  relative  convenience  and  economy  of  manufacturing 
and  handling  products  all  on  one  floor,  or  on  several  floors,  is 
important.  Elevator  service  costs  about  $25  per  day  for  each 
elevator,  not  simply  for  the  service  of  the  operator,  or  the  cost 
of  running  the  elevator  itself,  but  rather  in  the  amount  of  em- 


30  MILL  BUILDINGS 

ployees'  time  lost  in  waiting.  The  amount  of  lost  time  is  some- 
what reduced  by  using  several  elevators,  but  even  then  there  is 
waste.  There  is  also  loss  of  time  by  transferring  goods  from  one 
floor  to  another.  If  an  operator  desires  to  transfer  an  article  to  a 
point  on  the  floor  directly  above  him,  he  may  have  to  walk  half 
the  length  of  the  building,  wait  for  the  elevator,  ascend  to  the 
floor  above,  and  walk  back  again  to  the  place  designated.  He 
must  then  retrace  his  steps  over  the  same  route  to  his  own  place. 
Either  the  workmen  themselves  must  transfer  the  products  or 
others  must  be  employed  whose  duties  are  devoted  to  messenger 
and  delivery  service.  In  either  case  extra  expense  is  involved. 
In  one-story  buildings  there  is  a  corresponding  expense  for  trans- 
ferring, with  the  difference  that  the  delivery  distances  may  be 
less,  and  no  delay  or  loss  is  caused  by  the  maintenance  of  elevators. 

It  is  claimed  by  some  shop  superintendents  that  when  work- 
men are  all  on  one  floor  that  is  unobstructed  by  partitions,  and 
where  they  are  at  all  times  under  the  eye  of  the  superintendent  or 
foreman,  there  is  less  tendency  to  loafing  and  idleness  among  the 
employees.  It  is  also  claimed  by  these  advocates  of  one-story 
buildings  that  the  foreman's  office  should  be  so  located  that  every 
operator  on  the  floor  will  be  directly  in  view  and  his  presence  can 
at  all  times  be  seen  from  the  office.  The  wisdom  of  this  feature 
is,  however,  doubtful,  for  while  the  foreman  from  his  office  may 
be  able  to  see  all  the  employees,  he  has  no  assurance  that  their 
work  is  being  either  properly  or  effectively  done,  without  personally 
going  about  the  shop  and  inspecting  the  products  of  each  man's 
labor.  The  theory  of  the  single  floor  is  that  there  are  periods  in 
the  day  when  an  entire  floor  of  a  many-story  factory  may  be  left 
without  a  foreman's  supervision  during  hours  when  his  presence 
is  needed  on  other  floors,  and  at  such  times  there  is  idleness  and 
ineffective  work  among  the  men. 

The  area  of  one-story  factory  buildings  is  frequently  so  large 
that  it  is  quite  impossible  for  a  foreman  from  his  office  to  keep 
effective  watch  over  the  men  or  their  work.  He  should  be  out 
on  the  shop  floor  inspecting  at  close  range  what  is  being  done. 
When  a  single  floor  is  too  large  for  easy  inspection  from  one 
point,  one  of  the  supposed  merits  of  single-floor  buildings  dis- 
appears, for  it  requires  as  much  time  for  the  foreman  to  travel 
about  a  single  floor  as  it  would  to  travel  over  several  floors,  and 
if  he  is  unable  to  see  through  the  entire  length  and  breadth  of 
the  shop,  there  appears  to  be  nothing  gained  by  the  arrangement. 


NUMBER  OF  STORIES  31 

The  one-story  building  will  be  most  economical  in  shop  labor 
when  the  area  is  not  too  great. 

The  experience  of  some  single-story  shops  is  that  ventilation 
is  not  as  good  as  in  narrower  buildings,  and  that  workmen  become 
lethargic  and  do  less  work. 

(7)  Lighting.  Buildings  in  several  stories  can  be  lighted 
only  from  the  sides  and  ends,  and  as  side  lighting  in  low  stories 
is  not  effective  for  a  greater  distance  than  from  20  to  25  feet, 
buildings  in  several  stories  which  require  lighting  cannot,  there- 
fore, be  made  in  a  greater  width  than  from  40  to  50  feet.  The 
conditions  are  quite  different  in  one-story  buildings,  for  abundance 
of  light  can  then  be  brought  from  the  roof,  and  the  buildings  can 
be  made  as  long  and  wide  as  desired.  The  chief  objection  to  roof 
lighting  is  its  increased  cost. 


CHAPTER  V. 

WALLS. 

In  Part  IV  a  detailed  description  is  given  for  various  types  of 
walls,  together  with  their  comparative  costs.  In  this  chapter  it 
is  intended  only  to  outline  some  possible  forms  for  use  when  con- 
sidering the  general  requirements  and  features  of  a  manufacturing 
building.  The  minimum  thickness  of  walls  specified  in  the  build- 
ing laws  of  several  cities  is  given  in  Table  VI.  In  some  cases  the 
building  laws  may  determine  the  kind  or  thickness  of  walls  to 
use.  Building  laws  are  not  so  much  for  the  guidance  of  compe- 
tent engineers  as  they  are  for  the  restriction  of  incompetents  or 


Fig.   14. 

those  who  might  knowingly  violate  the  principles  of  safe  construc- 
tion; and  while  a  building  engineer  must  be  governed  to  some 
extent  by  building  laws,  he  should  follow  the  principles  of  safe 
construction,  as  well  as  law,  and  walls,  like  other  parts,  should 
be  proportioned  to  their  needs.  It  may  be  given  as  a  general  rule 
that  brick  side  walls  should  have  thicknesses  about  as  follows : 


(a)  Upper  story,  12  ins.  thick. 

(b)  Next  two  lower,  16  ins.  thick. 

(c)  Next  three  lower,  20  ins.  thick. 

(d)  Next  three  lower,  24  ins.  thick. 

(e)  Next  three  lower,  28  ins.  thick. 

The  following  types  are   those  most  frequently  used  in  mill 
and  factory  buildings: 


(1)  Stone  walls. 

(2)  Brick  walls. 


32 


WALLS 
TABLE  VI. 

REQUIRED   THICKNESS    OP    WALLS. 

According  to  Building  Laws  of  American  Cities. 


33 


Ten 

Stories. 
10 

Bos- 
ton. 
16 
20 
20 
20 
20 
20 
24 
24 
28 
28 

New 
York. 
16 
16 
20 
20 
24 
24 
28 
32 
32 
36 

Chi- 
cago. 
16 
16 
20 
20 
20 
24 
24 
24 
28 
28 

Minne- 
apolis. 
12 
16 
16 
16 
20 
20 
20 
24 
24 
24 

St. 
Louis. 
13 
18 
18 
22 
22 
26 
26 
30 
30 
34 

Den- 
ver. 
17 
17 
17 
21 
21 
21 
26 
26 
30 
30 

San 
Fran-   New 
cisco.  Orleans. 

9 
8 
7 
6 
5 
4 
3 
2 

1 

Nine  .  . 

.  9 

16 
20 
20 
20 
20 
20 
24 
24 
24 

16 
16 
20 
20 
24 
24 
28 
32 
32 

16 
16 
16 
20 
20 
20 
24 
24 
24 

12 
16 
16 
16 
20 
20 
20 
24 
24 

13 

18 
18 
22' 
22 
26 
26 
30 
30 

17 
17 
17 
21 
21 
21 
26 
26 
30 

•'•' 

•'•' 

8 
7 
6 
5 
4 
3 
2 
1 

Eight  . 

8 

6 
5 
4 
3 

2 

1 

16 
20 
20 
20 
20 
20 
24 
24 

16 
16 
20 
20 
24 
24 
28 
32 

16 
16 
16 
20 
20 
20 
24 
24 

12 
16 
16 
16 
20 
20 
20 
24 

13 

18 
18 
22 
22 
26 
26 
30 

17 
17 
17 
21 
21 
21 
26 
30 

•• 

13 
13 

18 
18 
18 
22 
22 
22 

Seven  . 

.  7 

16 
20 
20 
20 
20 
20 
24 

16 
16 
20 
20 
24 
24 
28 

16 
16 
16 
20 
20 
20 
20 

12 
16 
16 
16 
20 
20 
20 

13 
18 
18 
22 
22 
26 
26 

17 
17 
17 
21 
21 
21 
26 

•• 

13 
13 

18 
18 
18 
22 
22 

6 
5 
4 
3 

2 

1 

Six  ... 

6 
5 
4 
3 
2 
1 

16 
20 
20 
20 
20 
24 

16 
16 
20 
20 
20 
24 

16 
16 
16 
20 
20 
20 

12 
16 
16 
16 

20 
20 

13 
18 
18 
22 
22 
26 

13 
17 
17 
21 
21 
26 

13 
17 
17 
17 
21 
21 

13 
13 

18 
18 
18 
22 

Five  .  . 

5 
4 
3 

1 

16 
20 
20 
20 
20 

16 
16 
16 
16 
20 

16 
16 
16 
20 
20 

1-2 
12 
16 
16 
20 

13 
18 
18 
22 
22 

13 
17 
17 
21 
21 

13 
17 
17 
17 
21 

13 
13 

18 
18 
18 

Four  .  . 

.  4 

16 
16 
16 
20 

12 
16 
16 
16 

12 
16 
16 
20 

12 
12 
16 
16 

13 
18 
18 
22 

13 
17 
17 
21 

13 
17 
17 
21 

13 
13 

18 
18 

3 
2 
1 

Three  . 

.  3 

16 

16 
20 

12 
16 
16 

12 
12 
16 

12' 
12 
16 

13 

18 

18 

13 
17 
17 

13 
17 

17 

13 
13 
13 

9 
1 

Two  .  . 

2 
1 

12 
16 

12 
12 

12 
12 

12 
12 

13 
18 

13 
13 

13 
17 

13 
13 

34  MILL  BUILDINGS 

(3)  Combination  brick  and  concrete. 

(4)  Concrete  walls  with  light  steel  framing. 

(5)  Concrete  block  walls   (hollow). 

(6)  Concrete  and  expanded  metal — single  or  double. 

(7)  Sheet  metal  or  corrugated  iron. 

(8)  Plank  walls  or  movable  wooden  panels. 

These  may  be  constructed  in  any  one  of  three  general  ways, 
as — 

(a)  Solid  masonry  walls  without  columns. 

(b)  Light  masonry  curtain  walls  between  supporting  columns. 

(c)  Curtain  walls  of  wood  or  metal  sheathing  between  steel  or  con- 
crete columns. 

Solid  walls  should  be  built  with  pilasters  having  sufficient  area 
to  safely  sustain  the  loads  without  causing  a  greater  compressive 
stress  than  125  pounds  per  square  inch  on  brick  work  and  250 
pounds  per  square  inch  on  stone  and  concrete.  Wide  pilasters 
are  preferable  to  narrow  ones,  as  they  present  the  appearance  of 
greater  strength  than  those  which  are  narrower  but  deeper.  Solid 
masonry  walJs  are  satisfactory  for  buildings  in  which 

I      heavy  manufacturing  is  conducted  and  where  traveling 
cranes  are  used,  for  in  such  buildings  the  traveling 
cranes  cause  no  vibration.    Curtain  walls  are  not  so  sat- 
isfactory for  buildings  with  heavy  cranes,  for  they  lack 
rigidity,  and  when  once  the  framing  becomes  loosened, 
it  is  difficult  to  stiffen  the  building.    A  method  that  has 
been  found  effective  for  avoiding  vibration  in  buildings  where  cur- 
tain walls  are  used  is  to  first  erect  the  metal  framing  and  to  omit  the 
curtain  walls  for  a  month  or  two,  while  the  cranes  and  machinery 
are  in  operation.    The  bracing  may  then  be  inspected  and  all  loose 
rods   or  pieces  tightened,  and  the  frame  placed  in  adjustment. 
The  walls  are  then  built  in  solid  between  the  columns  and  there 
is   little   or  no   opportunity   for   vibration   to   occur.     When   the 
pilasters  of  solid  walls  would  be  excessively  large,  steel  columns 
may  be   inserted  in  the  piers.     A  column  made   of  four  angle 
bars  connected  with  a  plate  or  lattice  will  be  the  most  convenient 
(Fig.  15).     If  the  side  walls  or  pilasters  are  brick,  the  columns 
should  be  made  the  proper  width  so  that  brick  can  be  built  in 
and  around  the  column  with  the  least  amount  of  cutting.   Whether 
to  use  a  steel  column  in  a  masonry  pier  will  depend  principally  on 
the  cost  of  a  solid  pier  compared  to  the  corresponding  cost  of  a 
smaller  pier  with  a  steel  center.    In  some  cases  a  steel  column  may 
be  used  to  reduce  the  size  of  pier,  even  though  the  pier  with  the 


WALLS  35 

steel  center  would  have  a  greater  cost  than  a  larger  pier  without 
the  steel. 

There  are  many  matters  of  importance  that  must  be  carefully 
weighed  when  selecting  a  wall  for  any  prospective  building.  Cer- 
tain types  are  suitable  for  buildings  that  must  be  heated,  while 
others  are  not.  Forge  shops  or  buildings  where  excessive  smoke, 
gas  or  odors  occur  will  need  so  much  ventilation  that  the  walls 
may  well  be  made  of  movable  doors  or  panels  which  can  be  thrown 
open  or  removed,  and  the  whole  side  of  the  building  up  to  a 
height  of  eight  or  ten  feet  left  open.  This  arrangement  is  an 
excellent  one  for  blacksmith  shops,  where  there  is  not  only  excess- 
ive smoke,  but  where  workmen  are  liable  to  be  overheated  at  the 
forge.  The  open  sides  produce  good  ventilation  and  cause  an 
upward  draft  to  carry  the  smoke  away  through  roof  monitors. 
Buildings  in  which  the  walls  are  made  as  described  above,  with 
continuous  doors  (Fig.  16)  or  removable  panels,  should  have  a 


-t 90' *->- 

Lath  and  Cement  Plaster 


Fig.   16. 


continuous  line  of  sash  above  the  doors,  for  lighting  the  building 
when  the  panels  are  in  place  or  the  doors  closed.  If  the  total 
height  beneath  the  trusses  does  not  exceed  about  twenty  feet,  the 
entire  wall  space  above  the  movable  panels  may  then  be  covered 
with  sash;  but  if  the  height  exceeds  this  amount,  it  will  be  suffi- 
cient to  use  from  six  to  ten  feet  of  sash,  with  the  remaining  part 
of  the  wall  above  the  windows  enclosed  with  sheathing. 

Any  kinds  of  reinforced  concrete  walls  are  inconvenient  for 
buildings  where  extensions  or  additions  are  anticipated,  unless 
provision  has  previously  been  made.  As  these  walls  have  continu- 
ous metal  reinforcement,  it  is  difficult  to  cut  away  portions  of 
the  wall  or  to  make  openings  therein.  Concrete  walls,  especially 
those  of  a  single  thickness,  are,  however,  quite  economical  in  the 
amount  of  space  required. 

Where  there  is  any  probability  of  shop  walls  being  rammed  by 
cars  at  the  stub  end  of  tracks,  it  is  a  good  precaution  to  insert 
lintels  beneath  the  eaves,  so  the  roof  would  not  collapse,  even  if 


36  MILL  BUILDINGS 

a  car  or  locomotive  should  be  driven  through  the  wall.  In  pro- 
portioning wall  lintels,  economy  may  result  if  careful  examination 
is  made  to  ascertain  the  actual  load  that  bears  upon  the  lintel. 
In  solid  walls,  the  amount  of  load  will  usually  not  exceed  the 
weight  of  a  small  triangular  piece  of  masonry  above  the  lintel, 
but  this  will  depend  upon  the  position  of  the  adjoining  openings. 

Extra  large  doors  may  have  to  be  provided  for  the  admission 
or  removal  of  large  machines,  or  framing  arranged  so  a  panel 
can  be  removed  and  replaced  again  without  serious  inconvenience 
or  injury.  This  may  necessitate  the  omission  of  one  of  the  wall 
columns  and  the  insertion  of  a  truss  or  girder  to  carry  the  roof. 

The  following  table  gives  the  comparative  cost,  per  superficial 
square  foot,  for  walls  of  various  kinds.  The  estimates  are  based 
on  panel  lengths  of  20  feet  and  the  costs  per  square  foot  given 
include  not  only  the  wall  between  the  columns  but  also  the  cost 
of  the  wall  at  the  pilaster  or  pier.  They  are,  in  fact,  the  average 
square  foot  cost  of  the  entire  wall,  including  columns,  pilasters, 
water  table  and  plain  cornice. 

TABLE  VII. 

COST  OF  WALL  PEE  SQ.  FT.  Per 

Sq.  Ft. 

12-inch  stone  wall $0.50 

18-inch  stone  wall 70 

12-inch  brick  wall   (common  brick) 45 

8-inch  brick  curtain  wall  (common  brick),  steel  columns 46 

8-inch  brick  wall  (common  brick),  reinforced  concrete  columns 37 

8-inch  brick  curtain  wall  (face  brick),  reinforced  concrete  columns.  .  .     .52 

8-inch  concrete  wall,  light  steel  frame  and  steel  columns 46 

10-inch  concrete  block  wall,  steel  columns 37 

2-inch  concrete  and  expanded  metal  lath  on  steel  frame  (single) 33 

3-inch  concrete  and  expanded  metal  lath  on  steel  frame  (single) 36 

2-inch  concrete  and  expanded  metal  lath  on  steel  frame  (double) 54 

Galvanized  corrugated  iron  walls  on  steel  frame 28 

Plank  walls,  sheathed  on  steel  frame 31 

The  above  walls  are  those  best  suited  for  mill  and  factory  use. 
Comparative  cost  of  walls  finished  on  the  interior  and  suitable 

for  factory  offices  are  as  follows: 

Per 
Sq.  Ft. 
Wood  stud  walls,  weather  boarded  and  painted  on  outside,  and  lathed 

and  plastered  on  inside $0.18 

Wood  stud  walls,  with  4-in.   face  brick  veneer,   lathed   and  plastered 

inside    38 

12-inch    solid   brick   walls,    face   brick   exterior,   furred   and   plastered 

inside    62 

The  cheapest  of  these  walls  appears,  therefore,  to  be  corru- 
gated iron  supported  on  steel  frames.  Next  in  order  of  cost  are 


WALLS  37 

weatherboarded  plank  walls  on  steel  frames,  single  concrete  and 
expanded  metal  lath  on  steel  frames,  concrete  blocks,  and  light 
concrete  curtain  walls  between  reinforced  concrete  columns. 
Methods  of  determining  these  costs  closely  for  any  particular 
case  are  given  in  a  later  chapter,  on  Wall  Details. 

Solid  walls  of  either  stone  or  concrete  collect  condensation  on 
the  inside,  and  not  only  keep  the  interior  damp  but  the  wall  and 
floor  will  become  soiled  and  discolored,  making  them  less  desirable 
than  brick  or  some  form  of  hollow  walls.  Weatherboarded  plank 
on  steel  framing  has  a  low  first  cost,  but  has  a  high  insurance  rate 
and  is  a  poor  fire  risk.  An  ideal  factory  wall  is  made  by  using 
reinforced  concrete  columns  and  lintels,  with  a  thin  concrete  cur- 
tain wall  between  them,  the  whole  being  faced  on  the  exterior  and 
around  the  window  jambs  with  four  inches  of  bluff  or  yellow  face 
brick  secured  to  the  concrete  by  projecting  metal  wall  anchors. 
The  wall  has  the  merit  of  being  rigid,  the  light  steel  angles  in 
the  concrete  columns  being  sufficiently  strong  to  temporarily  sup- 
port the  trusses  without  any  covering,  and  permit  the  frame  to  be 
erected  rapidly  and  the  joints  easily  made.  It  has  the  additional 
merit  of  presenting  a  finished  appearance,  while  the  cost  is  not 
excessive. 


CHAPTER  VI. 

COST  OF  STEEL  BUILDINGS. 

Mill  and  other  industrial  steel  buildings  are  so  various  in  their 
forms  and  needs  that  it  is  difficult  if  not  impossible  to  give  rules 
for  their  weight  and  cost.  The  nearest  costs  that  can  be  given 
are  those  estimated  for  a  number  of  actual  buildings  of  various 
kinds,  and  these  may  serve  as  a  general  guide  in  deciding  upon 
the  probable  cost  of  proposed  new  ones.  Estimated  costs  are  bet- 
ter for  comparison  than  actual  ones,  for  external  conditions  can 
then  be  considered  more  nearly  uniform. 

The  buildings  described  in  this  chapter  are  all  original  designs 
by  the  author,  and  are  classified  under  the  following  headings : 

Buildings  with  Cranes,  and  Brick  Walls. 

Buildings  with  Cranes,  and  Corrugated  Iron  Walls. 

Buildings  with  Cranes,  and  Concrete  and  Expanded  Metal  Walls. 

Buildings  without  Cranes,  and  Concrete  and  Expanded  Metal  Walls. 

Buildings  without  Cranes,  and  Corrugated  Iron  Walls. 

Steel  Frame  Factory  Office  Buildings  or  Dwellings. 

Steel  frames  covered  with  corrugated  iron  or  metal  sheathing 
are  specially  suited  for  low  priced  buildings  in  tropical  or  semi- 
tropical  countries,  where  artificial  heating  is  unnecessary.  In  the 
following  pages  there  are  several  buildings  of  this  type  shown. 
The  cost  of  floors  and  foundations  is  not  included  in  the  prices 
given  unless  especially  stated,  for  these  can  usually  be  made  by 
local  builders  at  a  less  expense.  For  this  reason  it  is  customary 
for  foreign  buyers  or  owners  to  ask  for  quotations  on  the  steel 
superstructures  only,  not  including  either  ground  floors  or 
foundations. 

Buildings  for  export  to  foreign  countries  may  cost  more  in 
some  particulars  than  those  for  erection  in  the  United  States. 
The  various  parts  must  be  made  in  weights,  sizes  and  lengths 
which  can  be  conveniently  loaded  into  vessels.  Trusses  or  other 
large  pieces  which  could  be  shop-riveted  for  home  erection  may 
need  to  be  shipped  in  separate  parts,  in  order  to  be  loaded  into 
the  ship  hatches.  Some  additional  expense  may  be  incurred  on 
export  work  in  preparing  explicit  erection  drawings  and  in  mark- 
ing the  various  shipping  pieces  so  the  building  can  be  erected 

38 


COST  OF  STEEL  BUILDINGS 


39 


without  difficulty.  Occasionally  the  purchaser  of  a  building  for 
a  foreign  country  will  require  complete  drawings  of  his  buildings, 
and  these  drawings  may  have  to  be  made  in  metric  system.  This 
will  add  extra  expense,  as  American  shops  and  workmen  are 
more  accustomed  to  working  in  feet  and  inches  than  in  meters. 
There  is  also  the  expense  of  crating  small  or  loose  pieces  for  export, 
and  the  cost  of  ocean  freight,  as  well  as  loading  and  unloading 
the  material  from  the  vessel. 

BUILDINGS  WITH  CRANES— BRICK  WALLS. 

The  foundry  building,  100  feet  wide  and  200  feet  long,  shown 
in  Fig.   17,  has  brick  walls  without  side  columns,  and  the  roof 


Fig.  18. 

is  covered  with  No.  22  galvanized  corrugated  iron,  with  moving 
sash  in  the  side  walls  above  the  crane  runway.  The  framing  has 
25-foot  panels,  and  it  is  proportioned  for  a  20-ton  traveling  crane. 
The  iron  work  and  roofing  erected  complete  without  walls  cost 
$12,640,  which  is  equal  to  63  cents  per  square  foot  of  ground 
covered,  and  the  entire  building,  including  walls,  but  without 
floor  or  foundations,  cost  83  cents  per  square  foot  of  ground 
covered. 

Fig.  18  is  another  foundry  building,  80  feet  wide  and  100 
feet  long,  with  complete  inside  frame,  proportioned  for  a  10-ton 
traveling  crane.  It  has  tar  and  gravel  roof  on  2-inch  plank, 
with  brick  wall  on  one  side  and  two  ends.  The  other  side  has  a 
brick  base  5  feet  in  height  with  8  feet  of  glass  above  it,  finished 
with  a  2-inch  slab  of  concrete  and  expanded  metal  to  the  eave. 


40 


MILL  BUILDINGS 


•JacH  Rafters 


The  total  cost,  including  foundations,  is  $8,840 — equal  to  $1,10 
per  square  foot  of  ground  covered. 

Fig.  19  is  a  foundry  building  in  Ohio,  100  feet  wide  and  120 
feet  long,  with  brick  side  and  end  walls  without  wall  columns. 
It  has  a  slate  roof  on  small  angle  iron  purlins  spaced  10J  inches 
apart,  without  lining.  The  framing  is  proportioned  for  a  20-ton 
traveling  crane  and  the  steel  work  erected  cost  $7,200 — equal  to 
60  cents  per  square  foot  of  ground.  If  a  corrugated  iron  roof  had 
been  used  instead  of  slate,  there  would  have  been  a  total  saving 
on  the  building  of  about  $ly400 — equal  to  11  cents  per  square 
foot.  The  total  cost  with  walls  and  slate  roofing  is  $12,200,  or 
slightly  more  than  $1.00  per  square  foot  of  ground  area. 

Another    foundry   building   for   the   same   company,    100    feet 

wide  and  216  feet  long,  of 
the  same  general  design  as 
the  one  illustrated  above,  cost 
$11,200  for  the  steel  work 
erected — equal  to  52  cents 
per  square  foot  of  ground. 
The  total  cost,  including 
walls  and  slate  roofing,  was 
$19,000— equal  to  88  cents 
per  square  foot.  If  a  corru- 

Rafters  Bottom  Chords  gated  iron  roof  had  been  used 

^instead  of  slate,  there  would 
have  been  a  saving  in  the 
steel  work  of  $2,500. 

*Fig.  20  is  a  foundry 
building  for  Copenhagen, 
Denmark,  118  feet  wide  and 

230  feet  long.  It  has  a  galvanized  corrugated  iron  roof  with  sides 
and  end  of  brick.  The  crane  system  is  proportioned  for  a  30-ton 
traveling  crane.  The  roof  of  the  monitor  is  covered  with  glass 
and  on  the  monitor  sides  are  louvres.  There  are  steel  columns 
in  the  side  walls,  and  the  main  bents  are  15  feet  apart.  The  gal- 
lery has  wood  floor  on  steel  joist.  The  structural  work  weighs 
182  tons,  and  the  cost  of  the  steel  and  corrugated  iron  roof  erected 
is  $14,540 — equal  to  54  cents  per  square  foot  of  ground  area,  while 
the  entire  cost  of  building  complete  is  $22,000,  or  80  cents  per 
square  foot. 


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Fig.   19. 


COST  OF  STEEL  BUILDINGS  41 

BUILDINGS  WITH  CRANES— CORRUGATED  IRON  WALLS. 

Fig.  21  is  a  foundry  building,  80  feet  wide  and  203  feet  long. 
The  front  end  wall  facing  on  the  street  is  of  brick,  while  the 


WSm/MMJmJMSMWSWWMrtJbjJWSWWJWJMf 

v/s/w/XixmfwMMMw/M^^ 


Fig.   20. 

other  end  and  both  sides,  as  well  as  the  roof,  are  covered  with 
galvanized  corrugated  iron.  The  side  walls  and  rear  end  are 
lighted  with  10  feet  of  continuous  sash,  while  the  monitors  are 


42 


MILL  BUILDINGS 


covered  with  glass  and  have  ventilator  shutters  on  the  sides.  Trol- 
ley beams  beneath  the  trusses  with  capacities  of  two  tons,  deliver 
goods  to  two  large  doors  at  the  street  end.  The  cost  of  the  build- 


Fig.  21. 


Fig.  22. 


ing  complete  is  $12,880 — equal  to  84  cents  per  square  foot  of 
ground  covered.  The  structural  steel  weighs  100  tons.  One-half 
of  the  building  is  divided  into  machine,  pattern,  core,  and  ship- 
ping rooms,  and  there  is  an  office  40  feet  square  at  the  street  end. 


COST  OF  STEEL  BUILDINGS 


43 


This  is  one  of  the  most  acceptable  framing  outlines,  for  the  absence 
of  interior  gutters  avoids  any  possibility  of  leakage  and  laterally 
the  bents  are  well  braced  and  rigid.  The  center  line  of  columns 
also  reduces  the  weight  of  truss  framing.  When  greater  height  is 
needed  for  an  erecting  bay.  two  lines  of  interior  columns  can  be 
used  instead  of  one,  in  which  case  they  may  be  located  in  line 
with  the  monitor  sides. 

Fig.  22  is  an  alternate  design  for  the  above  building,  with  a 
single  ridge,  instead  of  two.  The  walls  and  roof  covering  are 
the  same  as  in  the  previous  design.  It  has  five  tons  more  steel 
framing  in  the  roof,  but  there  is  less  gable  wall  and  a  fewer 
number  of  monitor  shutters,  so  the  total  cost  is  but  little  more 
than  the  two-gable  design.  The  cost  per  square  foot  of  ground 
covered  is  85  cents  with  partitions  and  75  cents  without  them. 
The  corresponding  costs  per  square  foot  of  exterior  building  sur- 
face is  45  cents  and  40J  cents,  respectively. 

Fig.  23  is  a  machine  shop  for  the  Southern  States,  64  feet 
wide  and  128  feet  long,  with  16-foot  panels.  The  galleries  have 
plank  floors  on  wood  joist.  The  roof,  sides  and  ends  of  the  build- 
ing are  covered  with  corrugated  iron  on  steel  girths.  The  center 
erecting  bay  is  served  by  a  15-ton  traveling  crane.  The  cost  of  the 
steel  framing  erected  is  73  cents  per  square  foot  of  ground,  and 
the  total  cost  of  frame  and  corrugated  iron  is  95  cents  per  square 
foot. 

MfPlan  Rafters      Half  Plan  Beams 


Half 
6allery  Plan 


^ -K8.D  1 >; 


Half  Side  Elevation  Half  Long  Secfion 
Fig.   23. 

BUILDINGS    WITH    CEANES— EEINFOECED    CONCEETE    WALLS. 

Fig.  24  is  a  machine  shop   100  feet  wide  and  310  feet  long, 
with  tar  and  gravel  roof  on  a  3-inch  slab  of  reinforced  concrete, 


44 


MILL  BUILDINGS 


20  Ton  Crone 


and  walls  made  of  a  2-inch  slab  of  concrete  and  expanded  metal 

on  steel  girths.  It  has  provision  for  one  20-ton  traveling  crane, 

and  another  5-ton  at  a  lower  level. 
The  low  roof  trusses  are  13  feet 
apart,  while  the  higher  ones  over 
the  erecting  bay  are  26  feet  apart, 
and  there  are  steel  columns  in  the 
side  walls.  The  cost  of  the  steel 

h  _  _  -45.0;  .  _^ 55:0_  .  ^  work  erected  is  $12,700 — equal  to 

Fi  24  41  cents  per  square  foot — while  the 

whole  cost  of  the  building  is  $28,900 

— equal  to  95  cents  per  square  foot  of  ground  covered. 


\  5  Jon  Crane 


I^sC 


BUILDINGS  WITHOUT  CRANES—  REINFORCED  CONCRETE  WALLS. 

Fig.  25  shows  a  shop  45  feet  wide  and  200  feet  long,  having  a 
3-inch  reinforced  concrete  roof  covered  with  tar  and  gravel.  The 
walls  are  made  of  a  2-inch  slab  of  concrete  and  expanded  metal, 
on  light  metal  girths.  The  building  contains  40  tons  of  structural 
steel,  and  the  cost,  erected  complete,  including  steel,  gravel  roofing, 
doors,  windows,  walls  and  roof,  is  $5,570  —  equal  to  82  cents  per 
square  foot  of  ground  covered. 

*Fig.  26  is  a  one-story  warehouse,  50  feet  wide  and  200  feet 
long.  The  walls  consist  of  a  2-inch  slab  of  concrete  and  expanded 
metal  laths  over  light  steel 
girths.  The  building  has  a 
complete  steel  frame  with  side 
columns,  weighing  30  tons.  It 
is  lighted  entirely  from  a  sky- 
light* on  the  roof,  thus  per- 
mitting goods  to  be  piled  up 
against  the  walls,  without  ob- 
structing the  light.  It  has  a 
plank  roof  covered  with  tar 
and  gravel.  The  cost  complete 
is  $7,500  —  equal  to  75  cents 
per  square  foot  of  ground.  If 
8-inch  brick  curtain  walls  were 
used  between  the  steel  columns, 
instead  of  the  concrete  walls, 
the  cost  would  then  be  $8,200, 
or  82  cents  per  square  foot. 


Fig.  25. 


COST  OF  STEEL  BUILDINGS 


45 


BUILDINGS    WITHOUT    CEANES— WALLS     AND     EOOF    COEEU- 

GATED  IEON. 

*Fig.  27  is  a  gold  ore  mill  for  Johannesburg,  South  Africa.  It 
has  a  total  width  of  83  feet,  the  center  23  feet  being  occupied  with 
ore  bins,  while  30  feet  at  each  side  is  open.  Its  length  is  110 
feet.  The  building  is  covered  on  sides  and  roof  with  No.  22  gal- 
vanized corrugated  iron.  The  ore  pocket  is  lined  on  the  sides  and 
bottom  with  5-inch  plank,  and  it  contains  2,600  tons  of  ore.  The 
total  weight  of  steel  is  300  tons,  which  is  equal  to  7  pounds  for 


'//////y/////////w//w 

Fig.  26. 

every  cubic  foot  of  bin.  The  total  cost  of  the  building  is  $37,000 
— equal  to  $2.60  per  square  foot  of  ground  area  covered. 

*Fig.  28  is  a  steel  frame  sugar  warehouse  for  Porto  Eico,  to 
hold  20,000  bags  of  sugar,  piled  up  equally  on  the  two  'floors. 
The  building  is  fireproof,  with  brick  arch  floors  between  steel 
beams.  The  sides,  ends  and  roof  are  covered  with  corrugated 
iron.  The  weight  of  steel  framing  is  163  tons,  and  the  cost, 
erected  complete,  is  $17,000 — equal  to  $2.60  per  square  foot  of 
ground  covered. 

Fig.  29  shows  a  work  shop,  52  feet  wide  and  230  feet  long, 
for  South  Africa.  It  is  covered  on  the  roof  and  sides  with  No.  24 
galvanized  corrugated  iron.  There  are  five  ridges  running  crosswise 


46  MILL  BUILDINGS 

of  the  building,  instead  of  lengthwise,  in  the  usual  way.  The  loca- 
tion was  a  very  exposed  one,  and  the  framing  was  therefore  propor- 
tioned for  a  wind  load  of  30  pounds  per  square  foot.  Trusses 
and  columns  are  placed  13  feet  apart  and  columns  have  shafting 
brackets  3  feet  below  the  trusses.  There  were  400  separate  ship- 
ping pieces,  and  the  material  on  shipboard  occupied  9,000  cubic 


feet.  The  total  shipping  weight  was  80  tons,  and  the  total  cost 
of  the  building,  erected  complete,  was  $8,200,  which  is  equal  to 
60  cents  per  square  foot  of  ground  covered. 

**Fig.  30  is  a  market  building,  61  meters  wide  and  66  meters 
long,  for  South  America.  It  covers  a  whole  city  square,  having 
streets  on  four  sides.  The  building  is  made  entirely  of  steel, 
excepting  counters,  which  were  furnished  by  a  local  builder.  It  is 
divided  into  stalls  of  various  sizes,  from  10  feet  for  the  smallest 
to  20  feet  square  for  the  largest.  The  counters  are  accessible  by 
means  of  the  swinging  shutters  that  form  sunshades  when  open, 
and  at  night  are  shut  down  and  locked.  Ventilation  is  secured  by 
louvres  in  the  monitors  and  a  continuous  line  of  wire  netting 
underneath  the  eaves.  The  upper  part  of  all  partitions  is  made 


COST  OF  STEEL  BUILDINGS 


47 


of  wire,  thus  giving 
a  free  circulation  of 
air  throughout  the 
building.  The 
weight  of  steel 
frame  is  96  tons, 
and  the  total  ship- 
ping weight  is  185 
tons.  The  total  cost 
above  foundations 
i  s  $18,000 — equal 
to  53  cents  per 
square  foot  of  area 
covered. 

**Fig.  31  is  an- 
other market  build- 
ing, 50  meters 
s  q  u  are,  somewhat 
similar  to  the 
above.  It  has 
streets  on  only  two 
sides  and  is  made 
of  steel  and  glass, 
— 'excepting  the  wood 
counters.  On  the 
outside  are  swing 
doors,  which,  when 

open,  act  as  sunshades.  The  building  is  ventilated  by  fixed  louvres 
below  the  upper  eaves  and  also  on  the  sides  of  the  central  tower. 
There  is  also  around  the  building,  above  the  doors,  two  feet  of  wire 


A 

\ 

Assumed  Pile  of 

10,000  'Bags  of  Sugar     * 

t            .__, 

2 

1  , 

rTiePxk         \ 

Assumed 

Pile  of 

X 

10,000  Bags 

of  Sugar 

^ 

1 

1 

1  § 

1 

1  „  , 
1 

\ 

Fig.   28. 


Fig.  29. 


netting,  which  permits  a  free  air  circulation  at  all  times  through 
the  market.  Stalls  are  generally  10  feet  square.  The  area  cov- 
ered by  the  market  is  27,000  square  feet.  There  were  76  tons  of 
structural  steel  and  118  tons  in  the  whole  shipment.  The  cost  of 


48 


MILL  BUILDINGS 


COST  OF  STEEL  BUILDINGS 


49 


the  building  complete  is  $11,900,  which  is  equal  to  44  cents  per 
square  foot  of  area  covered. 

**Fig.  32  is  a  market  hall  for  the  City  of  Mexico.  It  is  fire- 
proof, the  roof  being  covered  with  galvanized  corrugated  iron, 
and  the  walls  in  expanded  metal  lath  and  concrete.  The  open 
arch  construction  for  the  sides  and  ends,  together  with  swinging 


Half     Section      C-  D. 


Fig.  31. 


"— ?.m85 >i 


windows  in  the  sides  of  the  monitors  and  dome,  give  ample  venti- 
lation. The  open  arches  are  provided  with  rolling  steel  shutters 
to  be  closed  at  night  or  when  desired.  The  extreme  outside  dimen- 
sions of  the  building  are  98  feet  by  230  feet,  while  the  dome  is 
50  feet  in  diameter.  It  covers  a  ground  area  of  22,540  square 
feet,  and  the  total  weight  is  102  tons.  The  total  cost  of  the  build- 
ing complete  above  the  floor  and  foundations  is  $22,000,  or  95 
cents  per  square  foot  of  area  covered. 


50 


MILL  BUILDINGS 


**Fig.  33  is  a  market  house  in  Moorish  style,  made  to  conform 
with  the  surrounding  architecture.  It  is  26  feet  wide  and  481 
feet  long,  with  three  towers  as  shown,  each  of  which  has  two 
floors.  On  the  second  floor  of  the  center  tower  is  a  tank  to 
supply  water  to  the  building.  A  notable  feature  of  this  market 
is  the  line  of  raising  shutters,  supported,  when  open,  on  small 
round  iron  columns.  These  shutters  form  also  a  continuous  sun- 


/\/\/ 

X 

7"^ 

rTl 

x 

;  I 

i_  1  

Fig.   32. 

shade  for  the  market  and  stalls.  The  building  is  ventilated  by 
means  of  swinging  windows  over  the  doors,  and  the  space  in  front 
of  these  windows  is  covered  with  ornamental  iron  grill,  the  win- 
dows remaining  open  over  night,  if  desired.  The  roof  is  covered 
with  galvanized  corrugated  iron,  and  the  sides  and  columns  are 
made  of  paneled  cast  iron.  The  filling  of  the  sides  above  the 
doors  is  made  of  stamped  sheet  metal  and  portions  of  the  tower  are 
ornamented  with  blue  tiles.  It  contains  78  tons  of  steel  and  its 


COST  OF  STEEL  BUILDINGS 


51 


total  cost  above  floor  and  foundations  is  $22,100,  or  $1.70  per 
square  foot  of  area  covered. 

**Fig.  34  is  a  market  building,  39  feet  wide  and  481  feet  long, 
with  complete  steel  frame,  and  covered  on  the  roof  and  sides  with 
corrugated  iron.  The  building  is  divided  longitudinally  in  panels 
13  feet  in  length.  The  two  end  houses  are  two  stories  in  height. 
The  center  portion  is  26  feet  wide  between  side  walls,  and  on  each 


Fig.   33. 


side  the  eaves  overhang  by  6J  feet,  forming  sunshades.  At  the 
center  of  the  building  is  a  5,000-gallon  water  tank,  to  supply 
water  to  the  market.  In  each  panel  there  is  a  swing  door  5  feet 
wide  and  8  feet  high,  which  is  raised  during  the  day  and  closed 
at  night.  Above  these  doors  is  3  feet  of  continuous  sash,  and 
between  the  sash  and  eaves  is  a  continuous  line  of  wire  mesh,  2 
feet  in  width,  for  ventilation.  Stalls  on  each  side  are  10  feet 


Fig.  34. 

deep.    The  total  cost  of  the  building  is  $12,900 — equal  to  68  cents 
per  square  foot  of  floor. 

**Fig.  35  is  a  market  building,  34  meters  wide  and  76  meters 
long,  covering  an  area  of  25,500  square  feet.  The  dome  is  68 
feet  in  diameter.  It  has  a  total  shipping  weight  of  137  tons,  and 
there  are  550  separate  shipping  pieces.  The  space  occupied  on 
board  the  vessel  is  13,000  cubic  feet.  The  weight  of  steel  is  about 
93  tons,  and  the  total  cost  is  $12,800,  which  is  equal  to  50  cents 
per  square  foot  of  area  covered,  not  including  either  floor  or  foun- 
dations. The  building  is  covered  on  both  sides  and  roof  with 


52  MILL  BUILDINGS 

galvanized  corrugated  iron.  The  curved  roof  gives  a  pleasing 
appearance.  There  are  no  partitions. 

Fig.  36  shows  a  steel  frame  market  building  for  export,  55 
feet  wide  and  150  feet  long.  It  is  in  the  form  of  a  cross,  with  a 
central  dome.  It  has  steel  frame  and  corrugated  iron  covering  on 
walls  and  roof.  The  floor  area  is  8,630  square  feet,  and  the  total 
cost  of  the  building  complete,  not  including  ocean  freight,  is 
$5,800 — equal  to  66  cents  per  square  foot  of  ground  covered. 

Fig.  37  shows  a  building  80  feet  wide  by  180  feet  long,  for 


Fig.  35. 

a  roller  skating  rink.  It  contains  67  tons  of  steel,  and  the  cost, 
erected  complete,  with  corrugated  iron  roof  and  walls,  including 
all  windows,  doors,  glazing,  etc.,  is  $8,975,  or  62  cents  per  square 
foot. 

SHOP  OFFICES  OR  DWELLINGS. 

*Fig.  38  is  a  two-story,  eight-room  portable  steel  house,  suitable 
for  tropical  countries.  It  has  a  wide  veranda  on  all  sides  at  each 
floor,  and  the  upper  story  has  a  paneled  sheet  metal  ceiling.  Be- 
neath the  eaves  are  open  spaces  covered  with  galvanized  wire  mesh, 
leaving  the  space  between  ceiling  and  roof  open  for  the  free  cir- 
culation of  air.  The  arrangement  prevents  the  upper  story  from 
becoming  excessively  hot  from  the  sun.  The  house  frame  is  bolted 


COST  OF  STEEL  BUILDINGS 


53 


together  and  may  be  taken  apart  and  erected  elsewhere  without 
injury.  There  are  two  floor  designs,  one  with  boards  on  wood 
joists  and  the  other  with  corrugated  metal  flooring  overlaid  with 


IXXIXXXXIXX 

Fig.  36. 


flat  steel,  and  the  space  between  filled  with  mud  or  sawdust.  The 
total  cost,  erected  complete,  is  $1,850,  and  the  shipping  weight  is 
24  tons. 


Fig.  37. 


54 


MILL  BUILDINGS 


Fig.  39  is  a  one-story,  six-room  house  or  office,  of  similar  con- 
struction to  that  above.  It  has  a  veranda  and  open  space  beneath 
the  eave  for  ventilation.  The  cost,  erected  complete,  is  $1,450, 
and  its  total  weight  is  20  tons. 


Fig.  38. 


-j.~.--4rrT 

,*£3l^         ^1;         T     I     '     I 


Fig.   39. 


Fig.  40  shows  a  four-room,  one-story  house  or  office,  with  a 
wide  veranda  on  two  sides  for  sunshade-  The  total  weight  of  the 
house  is  23  tons,  and  its  cost  is  $1,730.  The  floor  is  raised  about 
3  feet  above  the  ground,  and  the  whole  is  built  on  steel  sills.  The 


COST  OF  STEEL  BUILDINGS 


55 


building  requires  no  foundation  other  than  a  level  lot  or  site.  As 
the  joists  are  all  bolted,  it  can  be  taken  apart  and  removed  with- 
out injury. 

Fig.  41  is  a  steel  frame  factory  office  building,  40  feet  square, 
with  walls  and  roof  of  concrete  and  expanded  metal.  Its  total  cost 
is  $8,750,  including  floor  and  foundations.  It  is  all  in  one  room,, 
and  has  plaster  finish  on  the  inside,  with  an  open  fireplace  and 
chimney  in  the  center. 


Fig.  40. 


Fig.  41. 


TABLE  VIII. 

SUMMARY  OF  BUILDING  COSTS  AS  GIVEN  IN  CHAPTER  VI. 
Buildings  with  Cranes  and  Brick  Walls. 

Total  Cost  per  sq.  ft.  of 

No.                                                     Size.                          cost.  ground  covered. 

1.  Foundry,  without  walls,  100x200  ft $12,640  $0.63 

2.  Foundry,  with  walls,  100x200  ft .83 

2.  Foundry,  complete.  80x100  ft 8,840  1.10 

3.  Foundry,  steel  only,  100x120  ft 7,200  .60' 

3.  Foundry,  complete,  100x120  ft 12,200  1.00 

4.  Foundry,  steel  only,  100x216  ft 11,200  .52 

4.  Foundry,   complete,   100x216 19,000  .88 

5.  Foundry,  steel  and  metal,  118x230  ft.  . 14,540  .54 

5.     Foundry,  complete,  118x230  ft 22,000  .96 


56  MILL  BUILDINGS 

Buildings  with  Cranes  and  Corrugated  Iron  Walls. 

Total  Cost  per  sq.  ft.  of 

No.                                                   Size.                          cost.  ground  covered. 

6.     Foundry,  with  partitions,  80x203  ft $12,880  $0.84 

6.     Foundry,  without  partitions,  80x203  ft .75 

8.     Machine  shop,  steel  only,  64x128  ft .95 

8.  Machine  shop,  complete,  64x128  ft .73 

Buildings  with  Cranes,  Reinforced  Concrete  Walls. 

Total  Cost  per  sq.  ft.  of 

No.                                                     Size.                           cost.  ground  covered. 

9.  Machine  shop,  complete,  100x310  ft $28,900  $0.95 

9.     Machine  shop,  steel  only,  100x310  ft 12,700  .41 

Buildings  with  Cranes,  Reinforced  Concrete  Walls. 

Total      Cost  per  sq.  ft.  of 

No.                                                     Size.  cost.         ground  covered. 

10.  Shop,  complete,  45x152  ft $  5,570  $0.82 

11.  Warehouse,  complete,  50x200  ft 7,500  .75 

12.  Ore  mill,  complete,  83x110  ft 37,000  2.60 

13.  Sugar  house,  complete,  60x110  ft 17,000  2.60 

14.  Shop,  complete,  52x230  ft 8,200  .68 

15.  Market,  complete,  202x216  ft 18,000  .53 

16.  Market,  complete,  164x164  ft 11,900  .44 

17.  Market,  complete,  98x230  ft 22,000  .95 

18.  Market,  complete,  39x481  ft 21,000  1.70 

19.  Market,  complete,  39x481  ft 12,900  .68 

20.  Market,  complete,  112x250  ft 12,800  .50 

21.  Market,  complete,  55x151  ft 5,800  .66 

22.  Kink,  complete,  80x180  ft 8,975  .62 

Factory  Offices  or  Dwellings. 

Total  Cost  per  sq.  ft.  of 

No.                                                     Size.                           cost.  groand  covered. 

23.  Eight-room  house $1,850  

24.  Six-room  house 1,450  .... 

25.  Four-room  house 1,730 

26.  One-room    house,    40x40    ft .     2,750  

Eoughly  speaking,  one-story  steel  mill  buildings  with  cranes 
and  solid  walls,  erected  complete  without  ground  floor  or  founda- 
tions, will  cost  from  80  cents  to  $1.10  per  square  foot  of  ground 
covered,  while  similar  buildings  with  cranes  and  corrugated  iron 
walls  will  cost  from  70  cents  to  $1.00.  One-story  steel  frame  sheds 
or  buildings  without  cranes,  and  covered  with  corrugated  iron  will 
cost  erected  complete  from  50  to  70  cents  per  square  foot  of  ground 
covered. 

One-story  office  buildings  or  dwellings  erected  complete,  includ- 
ing floor  and  foundations,  cost  from  80  cents  to  $1.00  per  square 
foot  of  area  covered,  while  similar  two-story  buildings  cost  from 
$1.20  to  $1.50  per  square  foot. 

In  order  to  give  a  rough  idea  of  the  cost  of  steel  buildings  for 


COST  OF  STEEL  BUILDINGS  57 

export,  the  following  prices  are  given  for  the  material  delivered 
at  Atlantic  seaboard.  The  steamship  companies  do  their  own  load- 
ing, and  the  prices  given  are  for  material  delivered  at  the  wharf  and 
not  on  board  ship.  The  prices  are  for  all  material  for  complete 
steel  buildings,  including  steel  frame,  corrugated  iron,  doors,  win- 
dows, flashing,  gutters  and  conductors,  but  do  not  include  ground 
floors  or  foundations.  They  are  in  all  cases  for  buildings  covered 
with  metal  sheathing. 

The  material  for  machine  shops,  foundries,  etc.,  cost  from  40  to 
50  cents  per  square  foot  of  ground  covered. 

Sheds  and  other  buildings  proportioned  only  for  ordinary  roof 
and  wind  loads  cost  from  30  to  40  cents  per  square  foot  of  ground 
covered. 

A  fairly  close  estimate  may  be  made  for  sheds  and  other  plain 
iron  buildings  without  cranes,  by  figuring  all  the  exposed  surface 
of  both  walls  and  roof  at  30  cents  per  square  foot,  and  if  the 
building  contains  a  traveling  crane,  then  add  $1.00  per  lineal  foot 
of  building  for  every  ton  capacity  of  the  crane.  This  covers  crane 
supports  and  girders  only,  and  not  the  cost  of  crane  itself.  The 
cost  of  cranes  may  be  compiled  from  the  weight  given  in  Tables 
I,  II,  III,  IV,  XXII  and  XXIII. 


*  H.  G.  Tyrrell,  in  Engineering  News,  April  11,  1901. 
**  H.  G.  Tyrrell,  in  Architect's  and  Builder's  Magazi 


Magazine,  July,  1901. 


CHAPTER  VII. 

COMPARATIVE    COST    OF    WOOD,    STEEL    AND    REIN- 
FORCED CONCRETE  BUILDINGS. 

To  ascertain  definitely  the  comparative  cost  of  buildings  in 
wood,  steel,  and  reinforced  concrete,  an  examination  will  be  made 
of  two  typical  buildings,  and  the  cost  estimated  for  framing  them 
in  the  three  different  materials. 

The  first  of  these  buildings  is  a  bakery,  55  feet  wide,  88  feet 
long,  and  contains  seven  stories  and  a  basement.  It  differs  from 
other  factory  buildings  only  by  having  specially  heavy  framing 
on  portions  of  the  floor  to  carry  the  brick  bake  ovens.  These  ovens 
are  about  16  feet  square  and  10  feet  high  and  there  are  two  on  each 
floor.  This  feature  of  the  building  would  add  about  $3,000  to  its 
cost,  but  this  item  is  not  included  in  the  following  comparative 
estimates.  It  has  walls  and  windows  on  all  four  sides.  The  esti- 
mates given  are  for  the  structural  parts  of  the  building  only, 
including  walls,  columns,  floors,  framing,  roofing,  windows,  doors, 
excavation,  foundations  and  stairs,  but  do  not  include  plumbing, 
elevators,  heating,  partitions,  electric  wiring  or  lighting.  Neither 
do  they  include  any  miscellaneous  or  ornamental  iron  work  such 
as  store  front,  walk  lights,  coal  hole  covers  or  chute,  or  sidewalk 
grating.  The  cost  of  the  items  not  included  are  the  same  for  all 
the  estimates  and  are  given  below: 

Oven  framing $3,000      Heating    2,400 

Miscellaneous  iron 1,100      Electric  wiring 1,000 

Plumbing 3,100 

Elevator 1,500          Total   $12,100 

The  floors,  excepting  under  the  bake  ovens,  are  designed  to 
carry  a  uniformly  distributed  load  of  200  pounds  per  square  foot, 
including  both  dead  and  live  loads.  The  roof  has  a  flat  pitch  and 
is  designed  to  carry  a  uniform  load  of  100  pounds  per  square  foot. 
The  columns  are  designed  for  a  total  load  of  150  pounds  per  square 
foot  on  the  floors. 

The  thickness  of  the  basement  walls  is  24  inches  in  all  cases. 

The  various  plans  considered  are  as  shown  by  Figs.  42  to  48, 
and  are  as  follows : 

58 


COMPARATIVE  COST 


59 


Plan  A.  Complete  interior  and  exterior  steel  frame,  9-inch  cur- 
tain walls,  plank  floor  on  steel  beams,  all  steel  work 
fireproofed.  Total  cost  $49,100,  equal  to  $1.28  per 
square  foot  of  floors,  or  10.3  cents  per  cubic  foot  of 
buildings.  (Fig.  42.) 

Plan  B.  Interior  steel  frame,  brick  walls  17  and  13  inches  thick, 
plank  floor  on  steel  beams,  steel  work  fireproofed. 
Total  cost  $44,800,  equal  to  $1.16  per  square  foot  of 
floors,  or  9.4  cents  per  cubic  foot  of  the  building. 
(Fig.  43.) 


55-0 


Stories 

1-4    n" 
5-1  J3 

Walls 

Interior 

Steel 
Frame 

Plank 
Floor 



151-42* 
}—  ;  t7 



/III 
Complete 

Walls  9 
SteelFr 

7/775 

12  1  20  'k 

flank 

Floor 

Cement  _ 
Filling^ 


K~77-> 


^  Brick 


i;ht--"— — 


Figs.    42-43. 

Plan  C.  Complete  interior  and  exterior  steel  frame,  9-inch  curtain 
walls,  reinforced  concrete  floors,  columns  fireproofed. 
Total  cost  $52,000,  equal  to  $1.34  per  square  foot  of 
floor,  or  10.8  cents  per  cubic  foot  of  the  building. 
(Fig.  44.) 

Plan  D.  Interior  steel  frame,  brick  walls  17  and  13  inches  thick, 
reinforced  concrete  floors,  columns  fireproofed.  Total 
cost  $47,700,  equal  to  $1.24  per  square  foot  of  all  the 
floors,  or  9.8  cents  per  cubic  foot  of  the  building. 
(Fig.  45.) 

Plan  E.  Entire  building  reinforced  concrete.  Total  cost  $44,000, 
equal  to  $1.15  per  square  foot  of  all  the  floors,  or  9.1 
cents  per  cubic  foot  of  the  entire  building.  (Fig.  46.) 


gO  MILL  BUILDINGS 

Plan  F.  Part  interior  steel  frame,  not  fireproofed,  steel  columns 
and  two  lines  of  steel  beams  in  each  floor,  floors  slow 
burning  wood  construction,  brick  walls,  17  to  13  inches 
thick.  Total  cost  $40,600,  equal  to  $1.07  per  square 
foot  of  all  the  floors,  or  8.4  cents  per  cubic  foot. 
(Fig.  47.) 


Q> 
1 

f 

cC 

«K, 

1 

Ci> 

§ 



!5'l~4E^ 

V          ( 



-f 

*^ 

<0 

§ 

$: 

,»-s 

2Q 

i 

Cement 
Filling  •*. 


!*--/7~*i/ft7C/r 

'  r 


Plan  D 
;!  |!    Interior  Steel  frame 

Concrete  Floor  n         ji 
-ii     Walls  Stones  1-4  11-5-  1-  13 


11" 


Plan-C 
.Jjmplete  Steel  Frame 
Concrete  Floor 
9"~Throughout 


1  Cement  Finish  '** 


5  Reinforced  Concrete 


j^Armored 

Concrete  10 


Figs.  44-45. 


\ 

"—  j— 

t:::,.-.nv 

s 

^.-ij;r.---r.-) 

§         ii 

^.-.-.-.,,,J 

r"      T       -*• 

ij 

1 

I—, 

h  jj 

i,  —  i 

^ 

j.  :i 

' 

"••• 

Complete  Reinforced 
Concrete  Building 

fj 

-TT" 

L_  ..J 

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/  'Cemen't'Fini'sh  >           ! 

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Fig.  46. 


COMPARATIVE  COST 


61 


Plan  G.  Ordinary  slow  burning  construction  throughout,  with 
wood  columns  and  plank  floor  on  wood  beams  spaced 
5  to  6  feet  apart.  Total  cost  $37,000,  equal  to  96 
cents  per  square  foot  of  all  the  floors,  or  7.7  cents  per 
cubic  foot  of  the  entire  building.  These  figures  cor- 
respond closely  with  the  usual  cost  of  slow  burning 
wood  construction  for  200  pound  floor  loads. 
(Fig.  48.) 

In  plans  A  and  C,  if  alternate  courses  of  wall  girders  are 
omitted,  and  the  exterior  curtain  walls  carried  on  the  remainng 
girders,  the  total  saving  in  the  building  would  then  be  $1200, 
which  is  equal  to  3  cents  per  square  foot  of  floors,  or  i/4  cent  per 

PianF 
Part  Steel  Frame  Wood  Floor 


i        1                                        U 

«--%x—  > 

§ 

^     )   •                ®                ®               •  ¥  Y  / 

fc 

~T~ 

^f~  Steel  Columns 

1                     n, 

J 

£> 

"Q^ 







<g      * 

|        e         i         Ml 

7 

«:     k 
^ 
i 

Hu-  -  -  Wood  Columns 
J 

Plan  G 
Wood  Construction 

Figs.  47-48. 

cubic  foot  of  building.  In  case  alternate  wall  girders  are  omitted, 
a  channel  only  is  then  needed  on  the  inside  of  the  walls  at  these 
floors  to  carry  the  floor  loads. 

In  the  first  five  designs,  plans  A  to  E,  the  floors  are  6  inches 
thick  in  all  cases,  but  in  plans  F  and  G,  where  slow  burning  wood 
construction  is  used,  a  greater  floor  thickness  is  required. 

The  comparative  cost  of  the  floors  alone  in  plans  A,  B,  C  and  D, 
including  the  steel  beams  is  as  follows :  Wood  floors  cost  $7000, 
or  18  cents  per  square  foot,  while  reinforced  concrete  floors  cost 
$10,000,  or  26  cents  per  square  foot. 

In  computing  the  costs  in  all  the  above  cases,  the  total  area 
of  the  seven  floors  and  basement  is  taken  at  38,700  square  feet, 
and  the  total  cubical  contents  of  the  building  484,000  cubic  feet. 
The  height  of  building  from  cellar  floor  to  roof  is  100  feet.  A 
summary  of  the  above  comparative  estimates  is  as  follows : 


Q2  MILL  BUILDINGS 

Cost  per 

sq.  ft.  of  Cost  per  cu. 
Plan.                                                 Total  cost.               floor  surface,      ft.  (cents.) 

A    $49,100                          $1.28  10.3 

B    44,800                            1.16  9.4 

C    52,000                            1.34  10.8 

D    47,700                            1.24  9.8 

E    44,000                            1.15  9.1 

F    40,600                            1.07  8.4 

G    37,000                             .96  7.7 

Taking  the  cost  of  the  building  in  wood  mill  construction, 
estimate  G,,  as  a  basis,  and  calling  its  cost  unity,  the  comparative 
costs  of  the  other  methods  is  as  follows : 


TABLE  IX. 

A.  Complete  steel  frame,  curtain  walls,  plank  floor $1.30 

B.  Interior  steel  frame,  solid  brick,  plank  floor 1.19 

C.  Complete  steel  frame,  curtain  walls,  reinforced  concrete  floors....    1.37 

D.  Interior  steel  frame,  solid  brick  walls,  reinforced  concrete  floors.  ..    1.26 

E.  Entire   reinforced    concrete   building 1.17 

F.  Part  interior  steel  frame,  solid  brick  walls,  wood  mill  floors 1.09 

G.  Entire  wood  mill  construction,  slow  burning,  solid  brick  walls 1.00 

The  conclusion,  therefore,  from  these  estimates  is  that  a  building 
with  complete  steel  frame,  side  curtain  walls,  and  wood  floors  costs 
30%  more  than  wood  mill  construction,  while  the  same  building 
with  only  interior  steel  frame  and  solid  side  bearing  walls,  will 
cost  19%  more  than  wood  mill  construction.  If  the  first  building 
mentioned  above  had  a  reinforced  concrete  floor,  its  cost  would  then 
be  37%  more  than  mill  construction,  while  the  corresponding  cost 
of  the  second  one  with  reinforced  concrete  floor  would  be  26% 
more.  An  entire  building  of  reinforced  concrete  costs  17%  more 
than  one  in  wood  mill  construction.  If  steel  columns  and  two  lines 
of  longitudinal  steel  beams  are  used  at  floors  and  roof,  with  the 
balance  of  floor  and  roof  of  wood  mill  construction,  the  use  of  this 
partial  steel  frame  increases  the  cost  by  9%. 

It  appears,  therefore,  that  reinforced  concrete  buildings  cost 
17%  more  than  w^ood  mill  construction,  and  about  the  same  as 
buildings  with  complete  interior  steel  frames,  solid  walls,  and 
wood  floors. 

The  second  building  for  which  comparative  estimates  are  made, 
is  a  six-story  factory  building,  60  feet  wide,  100  feet  long,  contain- 
ing six  floors  and  a  roof,  as  shown  in  *Fig.  49.  The  floors  are 
designed  to  carry  an  imposed  load  of  100  pounds  per  square 


H.  G.  Tyrrell,  Canadian  Engineer,  October,  1904. 


COMPARATIVE  COST 


63 


foot.  Windows  are  on  all  sides  and  the  walls  carry  the  ends  of  the 
floor  beams.  The  walls  in  the  basement  are  24  inches  thick,  while 
in  the  first  four  stories,  they  are  17  inches.  The  remaining  two 
stories  have  13-inch  walls.  The  estimates  given  are  for  the  struc- 
tural parts  of  the  building  only,  including  walls,  columns,  floors, 
roof,  excavation,  doors,  windows  and  foundations,  but  do  not 
include  any  stairs,  partitions,  elevators,  plumbing,  heating,  wiring 
or  lighting. 

The  framing  of  the  slow  burning  design  is  as  follows :  Eight 
tiers  of  columns  spaced  20  feet  apart  in  both  directions,  carry  the 
floors  and  roof.  The  columns  from  the  roof  down  through  four 
stories  are  of  yellow  pine.  In  the  lowest  of  these  stories,  the  size 


YP 


Fig.  49. 

of  column  used  is  14x14.  Below  this,  where  a  greater  size  would  be 
required  than  can  be  secured  economically  in  wood,  round  cast 
columns  are  used,  llxlj  inches  in  the  first  story  and  12x1  J  inches 
in  the  basement.  All  the  columns  have  cast  iron  bases,  3  feet 
square  and  16  inches  high.  Lengthwise  through  the  building,  in 
the  floors,  run  two  lines  of  12x20-inch  yellow  pine,  which  rest  on 
brackets  of  cast  iron  column  caps.  The  cross  floor  beams  are  8x16- 
inch  yellow  pine,  spaced  5  feet  apart.  At  the  columns,  they  rest  on 
column  caps,  and  at  intermediate  points,  hang  from  the  12x20 
header  beams  by  means  of  wrought  iron  stirrups.  The  cross  floor 
beams  in  the  walls  rest  on  cast  iron  wall  plates,  9x20xf  inches. 
The  floor  is  made  of  f-inch  maple  laid  on  If -inch  yellow  pine.  The 
roof  is  similar  in  construction  and  has  a  tar  and  gravel  covering. 
The  quantities  of  material  in  the  building  as  outlined  above  are  as 
follows : 


64  MILL  BUILDINGS 

Excavation,    yds 1,800 

Cellar  cement  floor,  sq.  ft 6,000 

Foundation  concrete,  cu.  yds 150 

Brick,   cu.   ft 39,000 

Windows,  4  X  7  ft 238 

Koofing,    sq.    ft 6,000 

Yellow   pine   lumber,    ft.    B.    M 116,000 

Yellow  pine   flooring,   ft.   B.    M 73,000 

%  matched  flooring,  ft.  B.  M 46,000 

Iron  work,   tons 46 

The  estimated  cost  of  this  design  is  $35,000,  which  is  equiva- 
lent to  6.1  cents  per  cubic  foot  of  the  building,  or  83  cents  per 
square  foot  of  the  entire  area  of  all  the  floors.  The  interior  fram- 
ing of  floors  and  columns,  including  wall  plates,  column  caps,  bases 
and  stirrup  irons,  costs  27  cents  per  square  foot  of  floor  area. 

In  the  fireproof  design,  the  arrangement  of  beams  and  columns 
is  similar  to  that  used  for  the  slow  burning  design.  Riveted  steel 
columns  are  used  from  cellar  to  roof,  and  the  floors  are  framed 
with  steel  beams.  The  flooring  between  the  beams  is  reinforced 
concrete  and  the  arrangement  is  therefore  similar  to  plan  D  in  the 
previous  building.  The  quantities  are  as  follows: 

Excavation,  cu.  yds 1,800 

Cellar  floor,  sq.  ft 6,000 

Foundation  concrete,  cu.  yds 150 

Brick,  cu.   ft 39,000 

Windows,  4  X  7  ft 238 

Roofing,   sq.   ft 0,000 

Steel   columns,  tons 105 

Steel  beams  and  wall  plates,  tons 252 

Concrete    floors    and    roof,    sq.    ft 42,000 

The  cost  of  the  building  in  this  case  is  $57,000,  which  corre- 
sponds to  10.2  cents  per  cubic  foot  of  the  building  or  $1.36  per 
square  foot  of  the  entire  floor  area.  Floors  and  columns  cost  75 
cents  per  square  foot  of  floor  area.  Hence  comparative  estimates 

are  as  follows: 

Cost  per 

Cost  per    sq.  ft.  for 

Cost  per  cu.  ft.  of   floor  and 

sq.  ft.  of  building  cols,  only 

Total  cost.  floor  area  (cents).      (cents). 

Fireproof  steel  construction. $57,000  $1.36  10.2  75 

Wood  mill  construction 35,000  .83  6.2  27 

Figs.  50  and  51  are  views  of  a  two-story  steel  frame  work- 
shop, with  complete  steel  frame  and  walls  of  a  2-inch  slab  of  con- 
crete and  expanded  metal,  on  light  steel  purlins.  It  has  a  tar  and 
gravel  roof.  The  intermediate  floor  is  wood  mill  construction  with 
hard  pine  beams  spaced  5  feet  apart,  overlaid  with  two  layers  of 


COMPARATIVE  COST 


65 


plank.  The  building  contains  48  tons  of  structural  steel  and  its 
cost  erected  complete  is  $10,100,  equal  to  $1.35  per  square  foot  of 
ground  covered.  If  an  8-inch  brick  curtain  wall  were  used  instead 
of  the  concrete  and  expanded  metal,  the  cost  would  then  be  $11,000, 
or  $1.45  per  square  foot  of  ground. 


Fig.  50. 


A  two-story  factory  building,  40  feet  wide  and  100  feet  long, 
with  a  complete  steel  frame,  is  similar  to  the  last  one  described, 
except  that  the  second  story  is  free  from  inside  columns.  It  has  a 
2-inch  plank  and  gravel  roof,  with  walls  of  concrete  and  expanded 
metal.  The  intermediate  floor  has  two  layers  of  plank  on  wood 
beams  5  feet  apart.  The  total  cost  of  the  building  complete  above 


foundations  is  $5,400,  equal  to  $1.35  per  square  foot  of  ground 
covered.  It  contains  26  tons  of  structural  steel.  The  same  build- 
ing with  8-inch  brick  curtain  walls  instead  of  concrete  and  expanded 
metal,  would  cost  $5,800,  or  $1.45  per  square  foot  or  area  covered. 


66  MILL  BUILDINGS 

COST  OF  WOOD  MILL  CONSTEUCTION. 

The  cost  of  wood  mill  buildings  of  the  slow  burning  type,  with 
plank  floor,  wooden  beams  and  columns  and  brick  walls,  for  various 
widths  and  heights  of  one  to  five  stories,  has  been  given  on  the 
chart  Fig.  12.  For  widths  of  50  feet,  these  costs  are  about  as 
follows : 

TABLE  X. 
COST   OF  WOOD   MILL  CONSTEUCTION. 

Cost  per  sq.  ft.  Cost  per 

of  floor  area.  cu.  ft.  (cents). 

Mills,  3,  4  and  5  stories  high,  50  feet  wide.  .$  .85  to  $  .95  6.5  to  7.5 

Mills,  2  stories  high,  50  feet  wide 90  to    1.00  7.0  to  8.0 

Mills,  1  story  high,  50  feet  wide 95  to    1.05  7.5  to  8.5 

These  costs  are  for  northern  cities  and  do  not  include  parti- 
tions, plumbing,  heating  or  elevators.  If  these  items  are  included, 
the  cubic  foot  cost  would  then  be  increased  to  a  maximum  of  about 
11  cents.  In  country  districts  where  labor  is  cheaper,  the  cost  may 
be  15  to  20%  less.  In  the  South,  where  the  price  of  labor  and 
materials  is  from  30  to  50%  less  than  in  the  North,  the  prices  per 
square  foot  and  cubic  foot  will  be  reduced  accordingly.  Under 
the  most  favorable  conditions  in  the  South,  wood  construction  mills, 
not  including  the  items  above,  can  be  built  from  4J  to  5  cents  per 
cubic  foot.  The  cost  of  plumbing,  heating,  lighting  and  elevators, 
will  not  vary  greatly  between  the  North  and  South  and  these  items 
will  add  from  20  to  25  cents  per  square  foot  of  floor  surface  or 
from  1J  to  2  cents  per  cubic  foot,  to  the  cost  of  the  building. 

COST  OF  EEINFOKCED  CONCEETE  BUILDINGS. 

Costs  of  reinforced  concrete  manufacturing  buildings  in  heights 
of  one  to  five  stories,  and  widths  of  about  50  feet,  are  as  given  in 
the  following : 

TABLE  XI. 
COST  OF  EEINFOECED  CONCEETE  BUILDINGS. 

Cost  per  sq.  ft.  Cost  per  cu.  ft.  of 

of  floor  area.  building  (cents). 

Buildings,  3,  4  and  5  stories,  50  ft.  wide.  .$1.00  to  $1.10  7.5  to    8.5 

Buildings,  2  stories,  50  ft.  wide 1.05  to    1.15  8.0  to    9.0 

Buildings,  1  story,  50  ft.  wide 1.10  to    1.20  8.5  to  10.0 

The  prices  given  above  are  for  cities  in  the  northern  states  and 
do  not  include  partitions,  plumbing,  heating,  lighting  or  elevators. 
If  these  are  included,  the  cubic  foot  price  may  be  increased  to  12 


COMPARATIVE  COST 


67 


68  MILL  BUILDINGS 

cents.     In  country  districts  or  in  the  South,,  where  labor  is  cheap, 
the  above  costs  may  be  from  10  to  15%  less. 

Reinforced  concrete  buildings  will  cost  more  than  wood  mill 
construction  with  brick  walls,  by  15  to  20%  in  the  northern 
states  and  from  25  to  30%  in  the  southern  states,  where  wood  is 
abundant  and  less  expensive.  If  the  wood  mill  construction  has  a 
double  layer  of  diagonal  flooring,  the  above  differences  in  cost  will 
be  reduced  by  about  5%.  The  additional  cost  of  plumbing,  heat- 
ing, lightning  and  elevators  per  square  foot  and  cubic  foot  of  build- 
ing will  be  the  same  as  for  wood  construction,  which  has  already 
been  given. 


CHAPTER  VIII. 

ROOF  COVERING  AND  DRAINAGE. 

Any  kind  of  roofing  that  will  withstand  the  action  of  heat  and 
cold,  wind  and  rain,  snow  and  ice,  will  be  satisfactory.  The  chief 
essential  is,  however,  that  it  be  absolutely  water  tight. 

FIREPROOF  QUALITIES. 

The  building  laws  of  many  large  cities  specify  the  kinds  of 
roofing  that  are  accepted  in  the  fire  limits  of  their  municipalities. 
In  many  cases,  therefore,  there  is  little  or  no  choice  to  be  made, 
as  the  laws  require  that  all  roofs  within  certain  areas  shall  be  cov- 
ered with  non-inflammable  material.  Where  such  laws  do  not  exist, 
as  in  suburbs  or  rural  districts,  the  fire  risk  must  be  carefully  con- 
sidered and  comparative  insurance  rates  secured  for  roofing  of  dif- 
ferent qualities.  Investigation  of  insurance  charges  may  show  that 
a  net  saving  will  result  by  a  somewhat  larger  investment  for  a 
fireproof  roof.  If  the  interest  on  the  extra  expenditure  required 
for  a  fire-proof  roof  is  less  than  the  corresponding  insurance  charges, 
there  will  evidently  be  a  saving  by  the  use  of  the  expensive  roof. 

NON-CONDENSING  ROOFS. 

Condensation  on  the  under  side  of  roofs  is  caused  by  the  warm 
air  from  the  inside  of  the  building  coming  in  contact  with  the  walls 
or  roof  that  are  chilled  by  the  lower  temperature  from  without. 
Condensation,  therefore,  occurs  only  in  buildings  where  these  dif- 
ferent temperatures  exist.  Sheds  or  warehouses  with  open  sides  or 
storage  buildings  that  have  no  artificial  heating  will  not  be  subject 
to  condensation. 

On  a  certain  large  class  of  manufacturing  buildings,  it  is  abso- 
lutely necessary  that  the  roofs  be  so  designed  that  there  will  be  no 
condensation  or  dripping.  On  other  buildings,  the  matter  of  con- 
densation need  not  be  considered.  In  the  former  class  may  be 
placed  all  such  works  as  machine  shops,  power  houses,  dynamo 
rooms,  or  other  buildings  containing  valuable  material  and  products 
that  would  be  injured  by  water  falling  on  them.  Non-condensing 
roofs  are  required  only  on  such  buildings  that  must  be  heated  in 


70  MILL  BUILDINGS 

cold  weather  or  where  there  is  a  difference  in  temperature  between 
indoors  and  out. 

Condensation  may  be  avoided  in  buildings  that  need  no  artificial 
heating,  by  providing  enough  ventilation  and  air  circulation  so  that 
the  interior  of  the  building  will  at  all  times  maintain  the  same 
temperature  as  the  air  without. 

This  can  be  done  by  placing  ventilators  in  the  roof  and  air 
intakes  at  or  near  the  floor,  so  that  continuous  air  currents  may 
pass  into  the  building  and  out  again  through  the  roof. 

Any  form  of  roof  is  non-condensing  that  is  built  either  double 
or  with  a  ceiling  beneath,  in  which  there  is  an  air  space  between 
the  inner  and  outer  surfaces.  Wood  and  paper  are  poor  conductors 
of  heat  and  therefore  roofs  covered  with  plank,  the  joints  of  which 
are  overlaid  with  several  layers  of  building  paper  so  the  interior 
warm  air  cannot  reach  the  outer  sheathing,  will  be  subject  to  little 
or  no  condensation.  Eoofs  on  which  condensation  is  most  likely  to 
form,,  are  those  covered  with  sheet  metal  and  slate  or-  tile,  laid 
directly  on  purlins,  without  lining.  These  forms  of  roof  covering 
are  desirable  because  they  are  not  inflammable,  and  are  frequently 
used,  on  fireproof  buildings.  To  prevent  condensation  without 
introducing  any  inflammable  material,  several  patented  linings 
have  been  used,  one  of  which  is  shown  in  Fig.  54.  It  consists  of 
a  layer  of  strong  galvanized  poultry  netting,  tightly  stretched  over 
the  iron  purlins  which  are  trussed  or  braced  to  resist  bending  from 

the  tension  in  the  netting;  over  this 
are  laid  two  or  three  layers  of  asbestos 
paper  and  two  layers  of  Neponset 
building  paper,  above  which  the  roof- 
ing sheets  are  placed  and  secured  to 
the  purlins.  The  layers  of  paper  are 
Fig.  54.  shingled  one  over  the  other,  to  shed 

any  water  from  condensation  or  leakage.  A  weak  point  about 
this  patent  lining  is,  that  the  layers  of  paper  are  necessarily  per- 
forated by  the  bolts  or  wire  hooks  used  for  fastening  the  roof 
plates  to  the  purlins,  and  some  little  leakage  is  liable  to  run 
through  and  drip  from  these  bolts  or  wire  hooks.  A  good  rule 
is  to  have  no  metallic  connection  on  the  roof  between  the  interior 
and  exterior. 

EOOF  SLOPES. 

The  amount  of  slope  that  must  be  given  to  any  roof  will  depend 
to  some  extent  on  the  nature  of  the  covering.  Tin  roofs  with  the 


WOF  COVE  KING  AND  DRAINAGE 


71 


joints  all  soldered  tightly  in  both  directions,  with  no  chance  what- 
ever for  the  water  to  leak  through,  can  be  laid  at  any  slope,  either 
flat  or  steep,  as  desired.  Tar  and  gravel  roofs  can  be  laid  only  on 
surfaces  that  are  comparatively  flat,  where  the  asphalt  or  tar  will 
not  run  off  before  it  hardens,  or  even  after  completion,  as  the  tar 
will  soften  in  hot  weather  and  tend  to  run  if  the  inclination  be 
too  steep.  Their  slope  should  not  exceed  1J  inch  per  foot  and 
should  preferably  be  less.  Eoof  coverings  consisting  of  sheets  or 
plates  shingled  frver  each  other,  and  depending  only  on  their  slope 
to  shed  the  water,  must  have  a  sufficient  inclination  to  prevent 
driving  storms  from  blowing  rain  up  under  the  joints  and  causing 
leakage.  If,  however,  these  roofing  plates  or  sheets  are  laid  in 


Scale  Diagram  of  Roof  Pitches. 


Fig.  55. 


cement  to  make  the  joints  impervious  to  water,  it  is  then  safe  to 
lay  them  on  a  much  flatter  slope.  Fig.  55  shows  to  scale,  the 
various  roof  slopes  or  pitches  from  J  inch  per  foot  up  to  a  slope  of  45 
degrees. 

Eoofs  with  steep  pitch  are  mare  effective  in  quiekly  shedding 
rain  or  snow,  but  they  have  a  greater  area  to  cover  and  the  covering 
costs  proportionately  more.  Steep  pitch  roofs  are  generally  heavier 
than  flatter  ones,  because  they  carry  a  larger  area  of  covering  and 
because  the  truss  framing  is  also  somewhat  heavier.  The  steep 
pitch  has  a  larger  area  upon  which  the  wind  will  blow,  and  it  must 
be  proportioned  to  resist  those  additional  forces.  Flat  roofs  are 


72  MILL  BUILDINGS 

considered  safer  for  fire  protection  than  pitched  roofs  because  fire- 
men can  walk  upon  them. 

Table  XII  gives  a  list  of  common  roof  coverings  with  the  least 
pitch  on  which  they  should  be  laid.  Any  kind  of  wood  or  metal 
shingle,  slate  or  tile,  when  laid  in  the  ordinary  way,  should  have  a 
pitch  of  not  less  than  6  inches  per  foot,  but  if  any  of  these  are  laid 
with  joints  cemented,  the  pitch  can  then  be  as  small  as  3  or  4 
inches  per  foot.  The  various  kinds  of  prepared  roofings,  such  as 
Ruberoid,  Granite,  Carey's,  etc.,  and  sheet  tin  or  steel  with  soldered 
joints  or  standing  seams  can  be  laid  on  roofs  with  as  flat  a  pitch  as 
1  inch  per  foot,  while  tar  and  gravel  roofs  are  suitable  for  slopes 
varying  from  ^  inch  to  1  inch  per  foot. 

TABLE   XII. 
MINIMUM  EOOF  PITCHES  FOE  DIFFEEENT  COVEEINGS. 

Wood  shingles  on  plank Else      14  of  span 

Slate,    large Else      %  of  span 

Slate,    ordinary Eise      %  of  span 

Slate,   in  cement Eise    1/6  of  span 

Steel    roll    roofing Eise  1/12  of  span 

Euberoid    Eise  1/12  of  span 

Asbestos     Eise  1/12  of  span 

Asphalt    Eise  1/12  of  span 

Corrugated  iron  in  cement Bise      %  of  span 

Corrugated  iron  without  cement Eise      *4  of  span 

Composition    Eise  1/12  of  span 

Tar  and  gravel Flat. 

Tin  and  terne  plate Flat. 

Tile    Eise  7/12  of  span 


COMPAEATIVE    MEEITS. 

In  reference  to  duration,  slate  or  clay  tile  roofs  will  outlast 
all  the  other  forms,  and  if  desired,  may  be  removed  and  used  else- 
where, while  gravel  roofs  or  some  of  the  best  kinds  of  prepared 
roofing  will  be  next  in  durability  and  will  last  from  ten  to  twenty 
years.  Any  common  form  of  sheet  metal  roofing  will  soon  be 
destroyed  by  rust  unless  it  is  frequently  painted,  and  will  not  gen- 
erally last  longer  than  from  three  to  five  years. 

In  comparing  the  cost  of  roofings,  it  appears  that  some  of  the 
various  prepared  roofings  are  the  cheapest.  Other  kinds,  in  order 
of  cost  are  wood  shingles,  tar  and  gravel,  corrugated  iron,  standing 
seams,  sheet  steel,  metal  shingles,  slate,  tin,  corrugated  asbestos 
board  and  tile. 

Iron  or  steel  are  unsuitable  for  roofing  buildings  where  destruc- 


ROOF  COVERING  AND  DRAINAGE  73 

tive  fumes  or  gases  accumulate,  as  the  thin  metal  is  quickly  de- 
stroyed by  corrosion,  and  leaks  develop.  It  is  better  on  such 
buildings,  if  sheet  metal  is  preferred,  to  have  it  lead  coated,  as  on 
a  boiler  shop  for  the  Standard  Oil  Company,  designed  by  the 
writer,  where  the  roof  and  sides  were  covered  with  a  heavy  grade  of 
lead  coated  corrugated  iron. 

Metal  roofs  have  the  advantage  of  being  lightning  proof  and, 
as  the  roof  surface  is  smooth,  they  are  more  easily  kept  clean  by 
the  wind  and  the  rain.  If  it  is  desired  to  collect  rain  water  from 
the  roofs,  water  will  be  purer  when  taken  from  a  clean  metal  roof 
than  if  drained  from  one  of  tar  and  gravel.  Metal  has  the  dis- 
advantage of  transmitting  heat  and  cold,  and  metal  roofed  build- 
ings are  harder  to  heat  in  winter  and  in  summer  are  uncomfortably 
warm.  The  objection  to  plank  roofing  from  the  standpoint  of 
fire  risk  has  probably  been  overestimated,  for  heavy  plank  supported 
on  purlins  4  to  8  feet  apart,  will  at  the  worst,  burn  very  slowly,  and 
will  not  collapse  as  soon  as  light  steel  framing,  which  warps  and 
bends  quickly  under  heat.  Several  disastrous  fires  have  been  traced 
directly  to  this  cause. 

Slate  has  the  disadvantage  of  cracking  quickly  under  heat, 
should  fire  sparks  get  in  between  the  joints  and  ignite  the  boards 
below.  It  appears,  therefore,  that  the  selection  of  a  roof  covering 
will  depend  upon  the  necessity  for  its  being  fireproof  or  not,  the 
desired  amount  of  durability,  the  first  cost,  pitch  of  the  roof,  and 
the  amount  of  money  the  owners  are  willing  to  spend,  either  for 
the  sake  of  appearance  or  permanence. 

Red  slate  or  some  of  the  many  kinds  of  clay  tile,  especially  red 
or  green,  add  greatly  to  the  appearance  of  roofs,  though  at  extra 
cost,  but  this  additional  cost  may  easily  be  warranted  on  such 
buildings  as  pumping  stations  or  power  houses,  located  as  they 
often  are,  in  public  places  and  open  for  the  inspection  of  visitors. 

EOOF  DRAINAGE. 

The  primary  object  of  a  sloping  roof  is  to  shed  the  rain  and 
snow.  Snow  slides  from  its  own  weight  on  surfaces  inclined  at  an 
angle  of  about  45  degrees  to  the  horizontal. 

In  considering  the  subject  of  drainage,  roofs  may  be  divided 
generally  into  two  classes,  (1)  those  which  shed  the  snow  and 
water  entirely  to  the  exterior  of  the  building  and  (2)  those  which 
drain  all  or  part  of  the  roof  to  interior  gutters.  The  first  class  is 


74 


MILL  BUILDINGS 


illustrated  in  Bigs.  62,  64,  66,  67,  68,  74,  etc.,  while  the  second  is 
shown  by  Figs.  63,  69,  70,  71,  88,  80,  98,  etc. 

Draining  into  outside  gutters  has  the  advantage  that  no  shovel- 
ing of  snow  is  required  and  there  are  no  interior  gutters  to  collect 
dirt  which  may  cause  water  to  overflow  and  leak  into  the  buildings. 

The  objection  to  exterior  or  side  gutters  for  drainage  is  that 
snow  on  the  roof  which  is  easily  melted  by  heat  of  the  building 
from  within,  will  again  freeze  when  it  reaches  the  external  gutter 
at  the  eave,  and  the  freezing  will  cause  the  gutters  and  down 
spouts  to  burst  and  teak. 

One  benefit  to  be  derived  from  the  use  of  inside  gutters,  is 
that  they  permit  down  spouts  to  be  placed  within  the  building  in 
a  temperature  where  they  will  not  freeze  and  burat.  The  gutters 
being  over  the  building  which  is  heated,  are  less  liable  to  freeze 
and  can  be  mere  easily  thawed  out  should  freezing  occur,  than 


Fig.  56. 


Fig.   57. 


Fig.  58. 


Fig.  59. 


Fig.  60. 


Fig.  61. 


Fig.  62. 


Fig.  63. 


Fig.   64. 


Fig.   65. 


Fig.   66. 


Fig.  67. 


ROOF  COVERING  AND  DEAINAGE  75 


Fig.  68. 


Fig.  69. 


Fig-.  70. 


Fig.  71. 


Fig.  72. 


Fig.  73. 


Fig.  74. 


Fig.  75.  Fig.  76. 


Fig.  77. 


Fig.  78. 


Fig.  79. 


Fig.  80. 


Fig.  81. 


Fig.  82. 


Fig.   83. 


Fig.  84. 


Fig.   85. 


76 


MILL  BUILDINGS 


Fig.   86.  Fig.   87. 


Fig.   88. 


Fig.  89.  Fig.   90. 


Fig.   91. 


Fig.  92.  Fig.  93. 


Fig.   94. 


mi 


LLLL 


Fig.  95.  Fig.  96. 


Fig.  97. 


Fig.  98.  Fig.  99. 


Fig.  100. 


rvx^ 


Fig.  101.  Fig.  102. 


Fig.  103. 


Fig.   104.  Fig.  105. 


Fig.  106. 


ROOF  COVERING  AND  DRAINAGE  77 

when  placed  at  the  eave.  To  prevent  freezing  of  interior  gutters, 
it  is  customary  to  suspend  a  line  of  small  steam  pipes  directly 
beneath  the  gutter,  which  will  not  only  prevent  trouble  from  freez- 
ing, but  will  also  serve  as  a  part  of  the  general  heating  system. 
While  snow  will  accumulate  in  the  interior  gutters  in  the  winter 
season,  severe  storms  are  not  very  frequent,  and  even  when  they 
do  come,  there  is  little  liability  for  snow  to  accumulate  in  large 
quantities  on  roofs  which  are  exposed  to  wind.  Unless  the  snow  is 
heavy,  it  is  more  likely  to  be  blown  off  than  to  remain.  In  any 
case,  the  roof  will  be  sufficiently  strong  to  safely  carry  a  snow 
load,  and  the  expense  of  occasional  shoveling  is  not  great. 

A  shop  with  a  saw  tooth  roof,  built  in  1889  for  the  Straight 
Line  Engine  Works  at  Syracuse,  New  York,  required  snow  shovel- 
ing from  the  roof  only  once  in  seventeen  years. 

The  chief  objection  to  inside  gutters  is  their  extra  expense  and 
the  care  that  must  be  taken  to  keep  them  clean.  If  a  leak  occurs 
in  an  interior  gutter,  it  must  be  immediately  repaired  to  prevent 
water  running  into  the  building,  whereas  numerous  leaks  may  occur 
on  external  gutters  without  causing  any  damage,  and  individual 
leaks  will  not  necessitate  immediate  attention.  The  usual  custom  is 
to  ignore  separate  leaks  on  eave  gutters  and  renew  or  repair  them 
only  when  the  leaks  become  so  numerous  as  to  make  repairs  posi- 
tively necessary.  Saw  tooth  gutters  that  were  formerly  built  as 
shown  in  Figs.  313  and  317,  are  now  being  made  from  2  to  4  feet  in 
width  or  even  more,  in  order  that  there  may  be  less  chance  for  ice 
forming  and  bursting  them.  The  greatest  danger  from  leakage  re- 
sults when  ice  in  the  gutter  begins  to  melt.  The  water  is  then  drawn 
up  the  roof  slopes  under  the  ice  and  snow,  and  if  there  are  any 
openings  in  the  roof  up  to  the  surface  of  the  ice,  the  water  is  sure 
to  leak  through.  The  latter  form  is  illustrated  in  Figs.  101  and 
103.  Interior  gutters  should  be  very  carefully  designed  and  strongly 
built.  Various  details  of  both  interior  and  exterior  gutters  are 
given  in  Part  IV,  Chapter  XXVIII. 

GUTTER  PITCHES. 

Ordinary  eave  gutters  should  if  possible,  have  a  pitch  of  about 
1  inch  in  10  feet  and  never  less  than  1  inch  in  15  feet.  Interior 
gutters,  such  as  those  between  saw  tooth  trusses,  should  have  a 
greater  pitch,  or  about  J  inch  per  lineal  foot.  These  gutters  will 
drain  to  interior  downspouts  at  the  columns  and  their  steeper 
inclination  will  help  to  keep  them  clean  and  free  from  silt  or  dirt. 


78  MILL  BUILDINGS 

Unless  on  narrow  buildings,  there  should  be  no  effort  made  to 
drain  the  gutters  to  the  sides  of  the  building.  It  is  better  to  have 
them  drained  to  downspouts  placed  either  inside,  or  against  the 
interior  columns,  and  spaced  from  40  to  50  feet  apart.  The  gutters 
can  then  be  given  a  greater  slope  than  if  carried  a  longer  distance 
to  the  side  walls. 


CHAPTER  IX. 

LIGHTING  AND  VENTILATING. 

The  importance  of  proper  lighting  for  manufacturing  buildings 
is  evident.  The  amount  of  light  must  be  ample  but  it  must  not 
be  bright  or  glaring  to  cause  shadows  or  tire  the  eyes  of  the  work- 
men. Buildings  having  the  entire  wall  surface  composed  of  glass 
are  apt  to  be  so  bright  that  the  work  will  be  less  effective  than  in  a 
more  subdued  light.  The  effect  of  direct  rays  of  the  sun  on  large 
areas  of  glass,  even  though  they  are  protected  with  shades,  tends 
to  unevenly  light  the  interior  of  the  building  and  may  produce 
high  lights  where  they  are  not  needed  and  shadows  where  there 
should  be  the  best  light.  It  is  also  difficult  and  expensive  to  heat 
these  buildings  in  winter,  and  in  summer  they  are  excessively  warm 
because  of  the  heat  radiation  from  the  glass. 

The  subject  of  Lighting  will  be  considered  under  two  headings, 
(1)  General  Lighting  and  (2)  Specific  Lighting.  It  is  evident 
that  a  good  degree  of  general  light  should  exist  throughout  the 
working  space  of  any  manufacturing  building,  and  that  each  ma- 
chine or  particular  location  where  work  is  done,  should  be  well 
lighted  in  order  to  secure  the  highest  class  of  workmanship. 

All  manufacturing  or  industrial  buildings  will  not  necessarily 
require  either  the  same  amount  of  light  or  light  from  the  same 
directions.  Warehouses  in  which  goods  are  piled  around  the  walls 
will  often  require  very  little  or  no  light  from  ^he  sides,  and  per- 
haps none  from  the  roof.  Many  warehouses  are  in  use  only  when 
the  receiving  and  loading  doors  are  open,  and  such  openings  them- 
selves may  a^dmit  enough  light.  If, 'however,  more  is  needed  than 
will  enter  through  the  open  doors,  it  is  probable  that  light  from 
the.  roof  will  be  better  than  from  wall  windows  which  might  be 
obstructed  with  boxes  or  other  piles  of  goods.  In  warehouses,  if 
wall  windows  are  desired,  it  is  usually  better  to  place  them  high 
above  the  floor  and  make  them  only  large  enough  to  prevent  the 
warehouse  interior  from  being  dark. 

General  lighting  will  be  secured  in  one  of  the  followiog  ways : 

(1)  Side  wall  lighting, 

(2)  Roof  lighting  through  flat  skylight  in  the  plane  of  roof, 

79 


80  MILL  BUILDINGS 

(3)  Roof  lighting  through  longitudinal  monitors, 

(4)  Eoof  lighting  through  transverse  monitors, 

(5)  Eoof  lighting  through  box  skylights, 

(6)  Eoof  lighting  through  saw  tooth  roof  windows. 

Lighting  from  side  windows  is  effective  for  distances  not- 
exceeding  20  to  25  feet  and  for  this  reason,  buildings  in  several 
stories  or  those  depending  entirely  on  side  lighting,  cannot  usually 
be  made  of  a  greater  width  than  40  to  50  feet.  Buildings  that 
must  be  wider  than  50  feet  must  therefore  receive  additional  light 
from  the  roof. 

WALL  LIGHTING. 

Windows  in  factory  walls  have  been  made  in  a  great  variety 
of  ways,  depending  chiefly  on  two  factors,  the  first  of  which  is  the 
need  of  the  particular  building  or  the  kind  of  products  made  therein, 
and  the  second  factor  is  the  personal  preference  of  the  designer  or 
owner.  There  are  buildings  existing  with  side  windows  made 

(1)  Narrow  and  high, 

(2)  Low  and  broad, 

(3)  With  small  window  areas  near  together, 

(4)  With  large  window  areas  far  apart, 

(5)  With  continuous  sash  over  entire  wall, 

(6)  With  small  and  high  windows  above  the  floor,  etc.,  etc. 

In  many  of  these  buildings,  other  conditions  are  quite  similar 
and  products  the  same,  so  there  is  little  reason  for  the  great  diver- 
sity in  lighting  systems. 

The  quality  of  glass  also  differs  without  apparent  reason.  In 
some  places  ordinary  window  glass  is  used,  protected  inside  with 
shades,  while  in  other  places  the  shades  are  omitted  and  the  glass 
painted  white.  In  other  buildings  may  be  seen  windows  glazed  with 
ground  or  ribbed  glass  or  with  prisms,  though  the  cost  of  prism 
glass  is  generally  so  great  as  to  make  its  use  unwarranted  in  ordi- 
nary factory  buildings. 

The  general  use  of  plain  glass  for  side  windows  is  unsatisfac- 
tory on  account  of  the  need  of  either  inside  or  outside  shades. 
Under  the  most  favorable  circumstances,  the  duration  of  shades  in 
factory  buildings  is  short,  and  they  are  frequently  the  source  of 
disputes  or  discord  among  the  workmen.  Light  that  is  agreeable  to 
one  man,  may  be  disagreeable  to  another,  and  it  is  hard  to  adjust 
shades  to  suit  all.  On  this  account,  ribbed  glass  has  been  adopted 


LIGHTING  AND  VENTILATING  81 

entirely  in  some  new  factory  buildings,  for  all  side  window  open- 
ings, but  the  result  has  been  unsatisfactory  because  the  occupants 
of  the  building  are  then  unable  to  get  a  view  of  the  outdoors  or  to 
rest  the  eyes  by  changing  the  length  of  vision.  It  is  well  known 
that  the  eyes  quickly  grow  weary  from  continuous  observation  of 
objects  at  the  same  distance,  whether  near  or  far  away,  and  there 
is  no  better  means  of  resting  them  than  by  changing  the  view  to 
distant  hills,  sky  or  foliage,  even  though  these  changes  be  for  a 
few  moments  only.  It  is  therefore  unwise  to  use  ribbed  or  obscure 
glass  for  all  side  windows  of  a  factory  building,  but  it  is  still 
advantageous  to  use  ribbed  glass  in  the  upper  half,  as  the  ribbing 
tends  to  distribute  and  more  evenly  disseminate  the  light  over  the 
floor.  The  rough  glass  costs  about  the  same  as  plain  and  avoids  the 
use  of  shades.  The  experience  in  some  factories  where  ribbed  glass 
only  was  used  for  windows,  was  that  the  workmen  not  only  were 
unable  to  do  effective  work,  but  refused  to  continue  where  no 
opportunity  was  given  for  seeing  further  than  the  building  walls. 
It  has  been  found  that  the  amount  of  light  inside  of  a  building 
is  doubled  when  the  walls  and  framing  are  painted  white,  and 
hence  it  has  become  common  practice  to  paint  a  dark  colored  dado 
of  brown  or  green  about  5  feet  in  height  on  the  walls  and  columns, 
and  to  either  paint  white  or  whitewash  the  balance  of  the  interior. 

TOTAL  EEQUIEED  LIGHTING  AEEA. 

There  is  a  great  variation  in  the  amount  of  window  and  sky- 
light area  provided  by  different  designers  for  manufacturing  build- 
ings, so  great  indeed  that  it  would  seem  impossible  to  establish  any 
acceptable  rule  to  cover  the  subject.  The  required  area  of  glass  in 
walls  and  roofs  depends  on  several  conditions,  some  of  which  are, 
(1)  the  kind  of  glass  used,  (2)  the  prevailing  atmospheric  condi- 
tions, whether  clear  or  smoky,  (3)  the  use  to  which  the  building 
will  be  put,  (4)  proximity  to  other  buildings,  and  (5)  the  angle 
which  the  glass  makes  with  the  vertical.  A  shop  where  fine  detail 
work  is  carried  on  will  need  more  light  and  a  greater  area  of  glass 
than  a  forge  shop  or  rolling  mill,  and  if  color  work  is  done  in  con- 
nection with  detail,  a  still  greater  degree  of  light  will  be  needed. 
A  common  rule  for  lighting  is  to  make  the  glass  area  in  walls  and 
roof  equal  to  10%  of  the  entire  exterior  surface  for  mill  buildings, 
and  20%  for  machine  shops.  The  Pennsylvania  Steel  Company's 
new  buildings  have  windows  and  skylights  in  the  proportion  of  one 
square  foot  for  every  82  cubic  feet  in  the  buildings,  or  for  every 
2J  square  feet  of  floor  surface.  A  shop  for  the  American  Car  and 


82  MILL  BUILDINGS 

Foundry  Company  at  Detroit  has  27%  of  its  entire  exterior  surface 
composed  of  glass,  while  the  new  Engineering  building  at  the 
Brooklyn  Navy  Yard  has  glass  equal  to  60%  of  its  exterior. 

WALL  LIGHTING. 

A  good  general  rule  for  the  amount  of  wall  window  surface,  is 
to  make  such  area  not  less  than  20%  of  the  entire  wall.  Some 
designers  make  this  area  as  large  as  50%  of  the  wall  surface,  while 
another  rule  is  to  make  the  window  area  equal  to  the  square  root  of 
the  cubic  contents  of  the  shop. 

Other  rules  are  to  make  the  windows  not  less  than  10%  of  the 
floor  area  or  not  less  than  one  square  foot  of  window  for  every  100 
cubic  feet  of  shop  contents.  An  English  architect  says  that  the 
breadth  of  a  window  should  be  one-eighth  of  the  sum  of  shop 
width  and  height,  and  the  height  of  the  window  twice  its  breadth. 
The  new  plant  of  the  American  Bridge  Company  at  Ambridge  has 
side  window  areas  varying  from  20  to  30%  of  the  wall,  while  the 
new  Canadian  Pacific  Railway  shops  at  Montreal  have  side  win- 
dows equal  to  50%  of  the  entire  walls. 

EEQUIEED  SKYLIGHT  AREA. 

Mill  buildings  over  80  feet  in  width  should  receive  at  least 
half  the  light  from  the  roof  and  the  area  of  roof  lights  should  be 
about  one-half  the  entire  roof  surface.  The  new  General  Electric 
Company's  machine  shop  at  Schenectady,  New  York,  shown  in 
outline  in  Fig.  73  has  skylights  equal  to  40%  of  the  roof.  The 
skylight  area  on  the  St.  Louis  train  shed  is  equal  to  25%  of  the 
roof,  while  a  machine  shop  for  the  Chicago  City  Railway  Com- 
pany has  wire  glass  skylights  covering  35%  of  the  whole  roof. 

EOOF  LIGHTING. 

Figs.  66  to  74,  inclusive,  show  types  of  roof  having  two  rows  of 
interior  columns,  with  sash  or  windows  in  the  side  walls  above  the 
side  or  leanto  roofs.  The  amount  of  window  area  in  these  sides 
may  be  increased  or  diminished  as  desired  by  varying  the  height  of 
the  center  bay.  It  is  evident  that  for  the  same  height  beneath  the 
trusses,  Fig.  69  may  have  a  greater  window  area  on  the  side  than 
is  possible  in  such  a  design  as  Fig.  66,  but  it  is  also  evident  that 
the  framing  shown  in  Fig.  66  will  be  stiffer  laterally  than  69. 
Figs.  70  and  72  are  somewhat  similar  to  69,  inasmuch  as  the  side 
roofs  in  each  case  slope  inward  and  permit  a  greater  height  of 


LIGHTING  AND  VENTILATING  33 

glass  adjoining  the  central  columns.  There  are,  however,  other 
questions  beside  that  of  light  which  are  important  factors  in  tne 
selection  of  a  general  roof  outline  and  these  will  be  considered  in 
later  pages. 

FLAT  SKYLIGHTS. 

There  are  two  principal  objections  to  the  use  of  skylights  in 
the  plane  of  the  roof,  namely,  that  in  winter  seasons,  when  the 
roof  is  covered  with  snow,  light  is  liable  to  be  obscured;  and  they 
are  apt  to  leak.  To  overcome  these  objections,  the  skylight  at  the 
ridge  may  be  given  a  steeper  pitch  than  the  balance  of  the  roof,  as 
shown  in  Figs.  68,  84,  85  and  90.  The  increased  pitch  of  skylight 
will  tend  to  more  quickly  shed  the  water,  and  when  the  slope  is  as 
great  as  45  degrees,  snow  will  slide  off  by  gravity.  A  plant  of  this 
description  built  in  seven  transverse  bays,  each  bay  50  feet  in  width, 
has  been  constructed  for  the  Deutsche  Niles-Werkzeugmaschinen- 
Fabrik,  Berlin,  and  is  shown  in  Fig.  107.  The  design  is  somewhat 
different  from  current  American  practice  but  has  some  very  com- 
mendable features.  If  it  is  desired  to  use  north  light  to  avoid 
direct  sunlight  and  resulting  shadows,  these  ridge  skylights  may  be 
glazed  on  the  north  slope  only,  the  south  side  being  covered  with 
ordinary  roofing. 

LONGITUDINAL  MONITORS. 

To  be  of  any  value  for  lighting  purposes,  longitudinal  monitors 
must  have  sufficient  width  to  permit  the  direct  light  to  reach  all 
parts  of  the  floor.  Eoof  monitors  are  frequently  made  quite  nar- 
row, not  over  4  to  6  feet  in  width,  to  secure  better  ventilation. 
Windows  in  the  side  of  such  monitors  are  of  little  use  for  lighting, 
because  light  shines  across  the  monitor  and  very  little  reaches  the 
floor.  A  narrow  monitor  is  preferable  for  ventilation,  as  smoke  and 
impure  air,  rising  to  the  highest  part  of  the  roof,  are  then  drawn 
out  through  the  open  sides.  Monitors  for  lighting  should  have  a 
width  of  about  one-quarter  of  the  roof  span,  as  shown  in  Fig.  81. 
Light  entering  at  the  monitor  windows  will  then  be  unobstructed. 
With  this  width,  foul  air  and  gases  will  collect  in  the  upper  part  of 
the  roof  and,  if  the  building  is  one  where  smoke  and  gas  is  devel- 
oped to  any  great  extent,  it  may  be  necessary  to  use  a  second  narrow 
monitor  for  ventilation.  The  sides  of  this  smaller  monitor  may  be 
provided  with  sheet  metal  shutters  instead  of  windows,  as  the  amount 
of  light  from  the  sides  will  be  small.  Since  the  cost  of  movable 
sash  is  no  greater  than  the  corresponding  cost  of  shutters,  the  sash 


84 


MILL  BUILDINGS 


3ffl 


LIGHTING  AND  VENTILATING  85 

are  sometimes  preferred,  as  they  will  at  any  rate  light  the  upper 
part  of  the  roof,,  even  if  no  light  from  them  reaches  the  floor. 
Improved  forms  of  monitor  construction  are  shown  in  Figs. 
88,  91,  92,  93  and  94.  In  all  of  these  forms,  the  glass  is  inclined 
at  an  angle  of  about  45  degrees  or  less  with  the  vertical,  so  snow 
will  not  lodge  thereon,  while  a  larger  amount  of  light  is  admitted 
than  when  windows  stand  vertical.  Figs.  91,  92  and  93  have  no 
ventilator  monitor  and  occasional  movable  windows  are  required 
to  secure  circulation  of  air.  Figs.  88  and  94  haye  provision  for 
ventilation  above  the  sloping  glass  and  are  probably  the  most 
approved  and  acceptable  forms  for  shop  buildings  which  are  lighted 
through  continuous  monitors.  A  power  house  built  in  the  form  of 
Fig.  94  for  the  Pullman  Car  Company  at  Pullman,  Illinois,  has 
the  side  walls  above  the  sloping  skylights  set  out  a  distance  of  sev- 
eral feet  from  the  two  interior  rows  of  columns,  and  gives 
ample  clearance,  not  only  for  the  traveling  crane,  but  also  for 
swinging  a  sash  or  an  interior  footwalk  for  the  purpose  of  inspect- 
ing or  cleaning  the  monitor  windows. 

CKOSS  MONITORS. 

There  are  a  number  of  mill  buildings  lighted  through  the  roof 
by  means  of  occasional  transverse  -monitors  extending  either  part 
way  or  entirely  across  the  roof.  Fig.  79  shows  an  outline  sketch 
of  a  roof  recently  built  by  the  Jones  and  Laughlin  Company. 
Trusses  are  spaced  about  20  feet  apart  and  the  transverse  monitors 
shown  are  of  one  full  panel  length  and  occur  at  every  third  panel. 
The  entire  ends  of  these  transverse  monitors  are  filled  with  glass, 
and  the  designers  of  the  building  report  that  the  arrangement  is 
preferable  to  one  continuous  monitor  down  the  center  of  the  build- 
ing. Fig.  83  shows  a  somewhat  similar  roof,  built  for  the  Pencoyd 
Iron  Works. 

Assuming  the  trusses  to  be  20  feet  apart,  with  a  full  transverse 
monitor  over  every  third  panel,  the  cost  of  this  type  of  construction 
would  be  about  equal  to  the  cost  of  a  longitudinal  one,  when  the 
length  of  the  transverse  monitor  is  equal  to  three  panels  or  60  feet. 
If  the  transverse  monitors  have  a  less  length  than  three  panels, 
the  cost  will  then  be  less  than  the  corresponding  cost  of  longi- 
tudinal ones. 

BOX  SKYLIGHTS. 

Figs.  78,  80  and  82  show  forms  of  roofs  through  which  light 
is  admitted  to  the  floor  by  means  of  numerous  small  box  skylights. 


86  MILL  BUILDINGS 

These  skylights  may  serve  also  as  ventilators,  either  by  having 
movable  tops,  or  sides  of  sufficient  height  for  swinging  ventilators, 
sash,  or  louvres.  Numerous  skylights  have  the  advantage  of  dis- 
tributing light  uniformly  over  the  floor  but  they  are  apt  to  leak  and 
require  continual  care.  The  best  skylight  of  all  is  the  one  which, 
after  completion,  requires  no  attention  or  cost  for  maintenance. 

NORTHERN  LIGHT  ROOFS. 

The  type  of  roof  shown  by  Figs.  98  and  99  has  long  been  a 
favorite  for  use  in  southern  latitudes  where  little  or  no  snow  falls 
and  where  the  glare  of  the  sun  is  generally  bright.  For  a  long 
time,  it  was  not  used  to  any  great  extent  in  northern  climates, 
because  snow  gathers  on  the  roof  and  not  only  obstructs  the  win- 
dows but  produces  abnormal  roof  loads.  The  alternate  melting  and 
freezing  of  the  snow  from  heated  air  within  the  building  in  con- 
tact with  the  gutters  and  roof,  causes  ice  to  form  in  the  gutters 
which  frequently  bursts  them  and  makes  them  leak.  This  objec- 
tion of  snow  and  ice  does  not  occur  in  southern  climates  and  the 
type  is  therefore  particularly  suitable  for  these  locations. 

A  room  lighted  entirely  from  the  north  without  either  sunlight 
glare  or  shadows  is'  unquestionably  the  most  satisfactory.  To 
appreciate  the  difference  in  lighting,  it  is  only  necessary  to  examine 
and  compare  two  shops,  one  with  side  windows,  and  the  other 
with  northern  roof  light  only.  In  the  latter  shop,  while  every  part 
of  the  building  and  machinery  is  perfectly  lighted,  there  is  no  glare 
and  never  any  shadows.  The  principal  objection  to  a  more  general 
use  of  northern  light  roofs  is  their  excessive  cost,  but  as  more  and 
a  better  grade  of  work  can  be  done  under  the  better  lighting,  the 
extra  expenditure  is  frequently  warranted.  It  is  evident  from 
inspection  that  roofs  in  the  form  of  Figs.  98  and  99  have  a  greater 
cost  than  roofs  of  the  ordinary  types,  for  the  saw  tooth  roof,  espe- 
cially that  shown  in  Fig.  98  with  vertical  teeth,  has  a  greater  roof 
area.  The  whole  glass  area  is,  in  fact,  additional  over  the  area  of  a 
plain  pitch  roof  similar  to  Fig.  59.  The  angle  which  the  sash  makes 
with  the  vertical  must  be  small  enough  so  the  noonday  sun  at 
midsummer  will  not  strike  directly  on  the  glass.  The  magnitude 
of  this  angle  will  evidently  depend  upon  the  latitude,  but  in  the 
United  States  it  may  be  made  from  25  to  30  degrees,  or  somewhat 
greater  if  a  projecting  cornice  is  placed  above  the  glass,  to  serve 
not  only  as  a  finish  for  the  ridge,  but  also  to  shade  the  windows 
from  the  noondav  sun. 


LIGHTING  AND  VENTILATING  87 

To  exclude  direct  sunlight,  the  glass  must  face  directly  or 
very  nearly  north,  and  the  saw  teeth  may  be  placed  either  trans- 
versely or  longitudinally  on  the  building. 

It  was  formerly  the  custom  to  ventilate  saw  tooth  roofs  either 
with  circular  metal  or  steamboat  ventilators  on  the  ridge,  or  by 
making  all  or  part  of  the  side  windows  in  the  saw  teeth  movable. 
As  the  former  method  was  insufficient,  the  windows  were  frequently 
made  movable,  and  as  it  was  difficult  to  make  inclined  movable 
windows  weatherproof,  some  of  the  more  recent  saw  tooth  roofs 
have  the  windows  vertical,  as  show  in  Fig.  98.  This  precaution  is 
not  so  necessary  for  roofs  with  stationary  windows,  because  the 
joints  can  then  be  flashed  or  battened. 

Saw  tooth  windows  should  have  a  height  of  about  one-fourth 
the  truss  span.  They  should  be  double  glazed  in  northern  latitudes 
or  wherever  the  difference  between  inner  and  outer  temperatures 
is  considerable,  and  in  any  case  there  must  be  condensation  gutters 
beneath  the  sash.  The  forms  shown  in  96  and  97  have  the  advan- 
tage that  ventilation  is  secured  through  movable  sash  or  shutters  in 
the  upper  walls  of  the  center  bay,  and  the  saw  tooth  sash  in  the 
side  bays  may  be  fixed.  The  improvement  removes  the  danger  of 
leakage,  which  has  always  been  the  chief  objection  to  saw  tooth 
construction. 

Fig.  97  shows  the  general  outline  of  a  locomotive  shop  for  the 
Atchison,  Topeka,  and  Santa  Fe  R.  R.  Co.  at  Topeka,  Kansas.  A 
form  of  saw  tooth  has  been  proposed  as  shown  by  full  lines  in 
Fig.  102,  but  the  form  has  no  special  merit,  as  that  shown  by  dotted 
lines  could  be  built  at  a  less  cost  and  would  at  the  same  time  give 
a  greater  amount  of  light.  The  most  recent  and  approved  type 
of  saw  tooth  roof  is  shown  in  Figs.  101  and  103,  where  wide  gutters 
are  used  to  prevent  leaks.  Ice  forming  in  narrow  gutters  is  apt  to 
burst  them.  Fig.  101  is  an  outline  of  the  new  Carnegie  Steel  Com- 
pany's storehouse  at  Waver ly,  New  Jersey,  while  Fig.  103  is  a  roof 
at  the  American  Bridge  Company's  plant  at  Ambridge,  Pennsyl- 
vania. An  objection  to  using  wide  gutters  on  saw  tooth  roofs  is, 
that  beneath  the  gutter,  there  will  be  a  less  degree  of  light,  and 
for  this  reason  the  gutter  width  should  not  exceed  2  to  4  feet. 

North  light  may  be  secured  by  using  plain  skylights  on  one 
side  only  of  ordinary  pitch  roofs,  or  may  be  admitted  as  in  Figs. 
88,  89,  90,  91  and  92,  by  placing  sash  on  the  north  side  of  monitors, 
but  the  amount  of  roof  light  would  be  insufficient  for  ordinary 
shops. 

It  is  well  wherever  possible,  in  designing  roofs,  to  make  provi- 


88  MILL  BUILDINGS 

sion  for  some  form  of  narrow  foot  walks  near  the  monitor  sash  of 
skylights,  for  the  purpose  of  repairing  and  cleaning  them.  There 
are  but  few  features  about  a  manufacturing  building  which  show 
negligence  or  indifference  to  appearances  more  than  numerous 
broken  windows,  and  certainly  no  system  of  skylights  can  be  effect- 
ive even  though  designed  and  built  with  the  greatest  care,  if  the 
glass  is  allowed  to  become  covered  with  smoke  and  dirt.  Beating 
rain  storms  will  partially  cleanse  the  exterior  but  skylights  should 
be  accessible  on  the  interior  for  frequent  cleaning. 

VENTILATING. 

The  subject  of  ventilating  must  be  considered  when  deciding 
upon  the  general  roof  outline.  There  are  many  unfortunate  exam- 
ples of  manufacturing  buildings,  which  have  been  insufficiently 
planned  and  hurriedly  erected,  where  the  resulting  building  has 
proved  inadequate  to  its  purposes.  Men  cannot  work  at  their  best 
or  produce  work  of  the  best  quality  when  they  are  in  a  foul 
atmosphere.  Many  badly  ventilated  buildings  were  originally 
made  for  some  purpose  in  which  but  little  ventilation  was  needed, 
but  are  now  put  to  use  as  manufacturing  buildings,  and  gas  and 
smoke  accumulate  to  such  an  extent  that  effective  work  is  impossi- 
ble. Too  often,  short-sighted  management  refrains  from  adding 
me  necessary  ventilation  facilities,  knowing  that  the  cost  of  heat- 
ing in  the  winter  seasons  will  be  increased  thereby.  There  are 
plenty  of  proofs  of  increased  production  in  mills  and  factories 
built  on  modern  principles,  with  provision  and  thought  for  the 
comfort  and  welfare  of  the  workmen.  The  ventilation  of  manufac- 
turing buildings  is  so  important  that  it  is  now  being  scientifically 
treated  by  companies,  who  give  their  entire  attention  to  heating 
and  ventilating. 

Forced  ventilation  in  connection  with  the  heating  system  gives 
the  best  results,  and  many  modern  shops  are  now  using  it.  As 
artificial  ventilation  will  not  affect  to  any  great  extent  the  form  of 
the  roof,  further  than  providing  space  for  ventilation  ducts,  it  is 
not  necessary  to  discuss  this  part  of  the  subject  in  connection  with 
the  general  design.  In  many  buildings,  such  as  forge  shops  where 
smoke,  fumes  or  gases  occur,  artificial  ventilation  may  be  neces- 
sary. In  any  case,  the  amount  of  ventilation  required  will  depend 
upon  the  use  to  which  the  building  is  put  and  the  number  of  work- 
men that  it  will  accommodate.  Certain  kinds  of  manufacturing 
causing  but  little  smoke  or  gas,  may  require  no  more  ventilation 


LIGHTING  AND  VENTILATING  89 

than  is  easily  secured  by  an  occasional  open  window,  while  other 
buildings  will  need  continuous  lines  of  open  ventilators  in  the  roof 
with  intake  openings  near  the  floor.  Too  much  ventilation  is 
plainly  wasteful,  for  the  cost  of  heating  is  then  excessive  and  the 
results  are  no  better  than  where  there  is  less  ventilation  and  a 
correspondingly  less  amount  of  heat. 

Good  ventilation  is  as  essential  as  sanitation,  and  both  subjects 
are  receiving  their  deserved  attention  in  modern  manufacturing 
buildings.  The  need  of  ventilation  is  not  quite  so  evident  as  sani- 
tation, for  men  will  still  continue  to  work  in  impure  air,  wrho 
would  not  tolerate  old  unsanitary  conditions,  but  lack  of  proper 
ventilation  produces  a  stupifying  influence  on  workmen,  and 
lessens  their  productiveness.  Each  occupant  of  a  mill  or  factory 
should  have  hourly  not  less  than  200  to  300  cubic  feet  of  fresh  air, 
and  if  gas,  fumes  or  smoke  collect,  not  less  than  400  to  600  cubic 
feet,  with  an  additional  40  cubic  feet  per  hour  for  every  burning 
gas  jet.  Some  states  require  that  schools  and  public  buildings 
shall  have  1,800  cubic  feet  of  fresh  air  per  hour  for  each  person. 
Air  inlets  and  outlets  should  both  be  under  control,  for  too  much 
circulation  in  cold  weather  may  be  unnecessary,  while  it  will  add 
to  the  cost  of  heating.  If  too  much  warm  air  is  admitted,  and  too 
little  foul  air  discharged,  the  effect  will  be  to  produce  drowsiness 
on  the  workmen,  with  a  corresponding  loss  in  production.  The 
best  results  are  obtained  when  a  large  volume  of  air  is  admitted 
at  a  small  velocity,  keeping  all  the  air  in  motion  at  a  slow  speed, 
for  there  will  then  be  no  drafts.  When  air  is  admitted  through 
small  openings  at  high  velocity,  drafts  are  formed  which  may  result 
in  colds  and  sickness.  Heating  by  rapid  air  currents  at  high  tem- 
peratures, lacks  uniformity,  as  that  part  of  the  shop  adjoining  the 
air  inlets  will  be  too  warm,  while  other  parts  will  be  too  cold. 

The  following  table  gives  the  approximate  ventilation  area 
required  in  the  roofs  of  manufacturing  buildings  of  different  kinds 
per  100  square  feet  of  floor  area  for  side  wall  heights  of  20  to  50 
feet.  The  areas  are  net,  and  if  louvres  are  used  these  areas  must 
be  increased  by  about  60%  to  compensate  for  the  obstruction  caused 
by  the  louvre  slats. 

BEQUIRED    VENTILATION    AEEA. 

Height,  in  feet,  above  ground 20  30  40  50 

Machine  shops — square  feet %  %  %  %  Bound    ventilators 

Mills — square    feet    7  6  5  4  Louvre    ventilators 

Forge  shops — square  feet 9  8  7  6  Louvres — or   op«sn 


90  MILL  BUILDINGS 

HOOF  VENTILATION. 

The  following  are  the  common  methods  of  securing  roof  ventila- 
tion in  ordinary  manufacturing  buildings: 

(1)  Continuous  longitudinal  or  transverse  monitors,  with  louvre 

shutters, 

(2)  Saw  tooth  roof  construction  with  movable  windows, 

(3)  Ventilator  openings  in  roofs  as  shown  in  Fig.  77, 

(4)  Individual  circular  metal  ventilators. 

(5)  Box  skylights  with  open  sides  or  movable  tops. 

Continuous  longitudinal  monitors  as  shown  in  Figs.  64,  81,  94 
and  95,  with  movable  sash  or  shutters  on  the  sides,  ventilate  best 
when  they  are  narrow,  for  then  all  the  foul  warm  air  rising  to  the 
roof,  is  drawn  out  at  the  crown  and  none  is  allowed  to  remain. 
If  the  principal  monitor  is  intended  for  lighting  the  working  floor, 
a  second  narrow  one  may  be  added  at  the  ridge  as  shown  in 
Fig.  81. 

Transverse  monitors  shown  in  Figs.  79  and  83,  are  also  serv- 
iceable for  ventilation  when  the  sash  on  the  sides  are  movable. 
These  monitors  are  built  primarily  for  the  purpose  of  lighting  a 
building  interior  and  the  sides  would  therefore  be  covered  only 
with  sash  and  not  with  louvres  or  shutters.  Various  monitor  win- 
dows, shutters  and  louvres,  together  with  apparatus  for  opening 
and  closing  the  windows  and  shutters,  are  illustrated  in  detail  in 
Part  IV.  Trunnion  windows  give  a  larger  opening  or  ventilation 
area  than  those  which  slide  horizontally  or  vertically  past  each 
other,  for  in  the  latter  case,  only  half  the  window  area  is  available 
for  ventilation. 

SAW  TOOTH  VENTILATION. 

The  old  type  of  saw  tooth  roof  with  the  entire  roof  area  built 
on  the  same  system,  was  difficult  to  ventilate,  without  making  the 
windows  movable,  which  is  objectionable  on  account  of  being 
difficult  to  weather  proof.  For  this  reason,  some  recent  ones  have 
been  made  with  movable  windows  standing  in  a  vertical  plane 
and  therefore  less  liable  to  leakage  than  when  inclined  in  the  old 
way,  at  an  angle  of  about  25  degrees  to  the  vertical.  In  cases  where 
the  windows  have  been  made  stationary,  ventilation  is  secured  by 
means  of  ordinary  metal  or  steamboat  ventilators  on  the  ridge  as 
shown  in  Figs.  516  and  518.  The  effect  is  rarely  satisfactory, 
however,  for  the  air  does  not  move  at  a  sufficient  rate  to  keep  the 


LIGHTING  AND  VENTILATING  91 

atmosphere  fresh  and  agreeable.  Therefore,  in  some  of  the  most 
recent  saw  tooth  roofs,  the  side  bays  only  are  built  for  northern 
light,  while  the  center  bay  is  made  much  higher,  with  provision 
for  ventilation  either  on  the  sides  or  at  the  ridge,  as  shown  in 
Figs.  96  and  97.  This  arrangement  makes  almost  perfect  ven- 
tilation and  at  the  same  time  allows  the  northern  light  windows 
on  the  sides  to  be  stationary  and  water  tight.  It  is  best  not  to 
make  saw  tooth  shops  too  low,  with  a  minimum  height  of  12  to  14 
feet  beneath  the  trusses.  Low  roofs  have  the  advantage  that  the 
skylight  glass  is  near  the  work  benches,  with  consequently  better 
light,  and  there  is  less  expense  for  winter  heating,  but  in  summer 
the  heat  radiation  from  the  roof  is  oppressive  and  unless  forced 
circulation  is  used,  the  ventilation  may  be  insufficient. 

OPEN  ROOF  VENTILATION. 

A  plan  that  is  quite  effective  for  ventilating  very  smoky  build- 
ings where  little  or  no  artificial  heating  is  needed,  such  as  rolling 
mills,  furnace  buildings,  etc.,  where  there  is  always  excess  heat 
even  in  the  winter  season,  is  shown  in  Fig.  77.  Two  or  more 
lines  of  purlins  on  each  side  of  the  roof  are  built  with  upper  and 
lower  roof  supports,  and  continuous  open  spaces  are  thereby  left, 
varying  in  height  from  4  to  18  inches.  The  upper  roof  projects  far 
enough  over  the  lower  one  to  shed  any  ordinary  rain  or  snow,  and 
where  large  volumes  of  gas,  fumes  or  smoke  arise,  these  continuous 
openings  are  effective  in  clearing  the  atmosphere. 

INDIVIDUAL  METAL  VENTILATORS. 

Ventilators  of  this  kind  are  shown  in  Figs.  62  and  72,  and  in 
detail  in  Part  IV,  Chapter  XXIX.  They  are  suitable  only  when 
a  small  amount  of  ventilation  is  needed.  Numerous  patent  forms 
are  on  the  market  known  by  various  names,  such  as  Globe,  Star, 
etc.,  but  they  are  easily  made  in  almost  any  sheet  metal  shop  with- 
out the  need  of  paying  patent  royalties.  An  objection  to  the  use  of 
these  ventilators  is  that  the  warm  air  from  the  interior  of  the 
building  coming  in  contact  with  the  metal  at  a  very  much  lower 
temperature  in  the  winter  season,  will  cause  condensation  that  is 
liable  to  be  damaging  to  the  contents  of  the  building,  unless  con- 
densation gutters  are  used.  The  steamboat  ventilator  shown  in 
Fig.  516  is  made  with  double  sides  to  prevent  this.  Circular  metal 
ventilators  should  preferably  have  dampers  to  be  opened  or  closed 
at  will.  The  following  table  gives  the  area  of  circular  ventilators 
for  diameters  from  12  to  48  inches: 


92  MILL  BUILDINGS 

AREA  OF  CIRCULAR  VENTILATORS. 

Diameter  in   ins 12         18         24         36         38         42         48 

Area  in  sq.   ft 8        1.8        3.1        4.9        7.1        9.6      12.6 

BOX  SKYLIGHT  VENTILATORS. 

These  are  more  or  less  effective  when  the  curbs  or  sides  of  the 
boxes  are  provided  with  movable  sash  or  shutters  or  covered  with 
louvres.  On  account  of  their  being  separated,  they  require  indi- 
vidual attention  and  are  not  as  convenient  as  monitor  windows 
which  oan  be  opened  in  groups  with  a  single  chain  or  hand  wheel. 

SPECIAL  VENTILATORS. 

Certain  buildings  require  special  ventilation.  It  is  common 
practice  to  ventilate  engine  houses  by  lowering  a  funnel  or  smoke 
jack  over  the  engine  stacks. 

Many  modern  blacksmith  shops  are  ventilated  by  placing  in- 
verted hoods  or  funnels  above  the  forges  and  drawing  all  smoke 
and  fumes  away  to  a  ventilation  stack  by  suction  which  not  only 
draws  the  smoke  but  also  keeps  the  air  in  circulation  in  the  building 
(Fig.  108).  In  Germany  a  method  has  recently  been  used  for 
ventilating  by  a  central  tower. 


Fig.   108. 
WALL  VENTILATION. 


Shops  which  require  no  artificial  heating  can  be  effectually 
ventilated  by  building  the  lower  10  feet  of  wall  in  the  form  of 
continuous  doors  or  movable  panels.  The  latter  are  the  cheaper, 


LIGHTING  AND  VENTILATING  93 

but  are  troublesome  to  remove  and  replace,  as  they  are  bolted  to 
the  frame  work. 

When  a  plant  is  enclosed  with  a  fence  or  wall  and  watchmen 
are  on  guard  both  day  and  night,  it  may  be  unnecessary  to  close 
the  buildings  at  night  when  the  workmen  are  absent,  and  the 
movable  panels  would  then  be  as  effective  as  the  more  expensive 
doors.  They  may  be  made  as  large  as  can  be  conveniently  handled. 
6  or  8  feet  in  width  and  about  10  feet  in  height,  and  in  the  spring- 
time, when  weather  conditions  will  permit,  may  be  unbolted  and 
removed  to  a  convenient  place  for  storage,  there  to  remain  until 
again  required  on  the  approach  of  cool  weather  in  the  autumn. 
Panels  may  be  made  of  either  wood  or  sheet  metal,  as  preferred. 

Ventilation  is  greatly  facilitated  by  placing  a 
line  of  shutters  in  the  wall  at  or  near  the  floor, 
which,  when  opened,  will  cause  a  current  of  air  to 
circulate  upward  through  the  building,  carrying  the 
foul  air  and  smoke  out  through  the  roof  ventilators. 
These  may  be  made  as  part  of  the  movable  panels 
as   above  described,   so  that  in  winter,   when  the 
weather  will  not  permit  the  opening  of  the  entire 
side,  some  or  all  of  these  small  ventilating  panels 
may  be  used  as  desired.    When  the  sides  are  made 
of  doors  instead  of  movable  panels  (Fig.  16),  the 
cost  will  be  more  because  of  the  necessity  of  sus- 
pending or  hinging  them.     It  is  generally  imprac- 
ticable to  hinge   large  doors  on  account  of  their 
weight,  for  sooner  or  later  the  weight  will  cause 
them  to  droop  and  their  movement  to  be  impaired. 
A  vertical  sliding  door,  counterweighted  at  both 
sides,  is  satisfactory  for  continuous  side-openings,         Fig.  109! 
if  there  are  large  window  panels  in  the  door  to  per- 
mit the  light  to  enter  from  the  side  wall  windows.     Some  form  of 
folding  door  such  as  is  shown  in  Part  IV,  Chapter  XXXVI,  is  suit- 
able for  continuous  side  openings.    These  may  be  made  in  wood  or 
metal,  as  preferred.     Certain  buildings  may  be  left  open  at  the 
sides  during  all  seasons  of  the  year.    In  this  class  are  such  buildings 
as  storage  sheds,  furnace  houses  or  others  which  are  used  both  day 
and  night  and  have  at  all  seasons  excessive  heat. 

A  method  of  wall  ventilation  used  by  the  writer  in  designing  a 
wool  treating  warehouse  is  shown  in  Fig.  109.  The  walls  are  20 
feet  in  height  and  are  covered  with  sheathing  in  three  lengths  and 


94  MILL  BUILDINGS 

at  the  joints  where  the  layers  of  sheathing  overlap  each  other  the 
purlins  are  framed  to  permit  4-inch  air  spaces  around  the  entire 
length  of  sides  and  ends,  interrupted  only  by  the  windows.  Beneath 
the  overhanging  eaves  there  is  another  continuous  4-inch  air  space. 
On  the  roof  at  the  ridge  is  a  monitor  ventilator  with  3  feet  of 
continuous  metal  louvres  on  either  side,  so  that  at  all  times  there 
is  free  circulation  of  air  through  the  building. 


PART  II 
LOADS 

CHAPTEE  X. 

STATIC  ROOF  LOADS. 

Mills,  factories  and  other  industrial  buildings  differ  so  greatly 
in  their  purpose  and  use  that  it  is  difficult  to  establish  any  rules  or 
formulae  for  the  weight  of  material  in  them.  Each  building  must 
be  considered  separately,  and  after  its  requirements  are  known  and 
its  general  outline  selected,  the  approximate  amount  of  material 
and  the  corresponding  weight  may  then  be  determined.  The  amount 
of  material  will  depend  upon  the  use  and  character  of  the  building, 
whether  temporary  or  permanent,  fireproof  or  otherwise,  the  loads 
that  it  must  carry,  the  nature  of  the  roof  covering  and  the  presence 
or  absence  of  cranes  or  other  handling  appliances. 

The  loads  to  which  these  buildings  are  subject  are  as  follows: 

Dead    Loads.  Live  Loads. 

(a)  Roof  Framing  and  Covering.  (d)  Snow. 

(b)  Walls.  (e)  Wind. 

(c)  Floors.  (f)  Cranes. 

(g)     Pipes,  Shafting,  etc. 

In  the  following  pages,  these  various  loads  are  considered  sepa- 
rately in  detail,  and  tables  of  weights  are  given.  It  is  advisable  to 
make  liberal  provision  for  future  increased  loads,  as  experience 
shows  that  buildings  are  frequently  subjected  to  much  harder  usage 
than  anticipated.  There  must  also  be  liberal  additions  to  the 
stresses  from  cranes  or  other  moving  loads  to  provide  for  impact 
and  vibration  which  tend  to  jar  and  rack  the  building.  This  impact 
addition  must  be  made  in  designing  both  the  frames  and  the 
foundations. 

The  maximum  loads  of  every  nature  must  be  positively  known 
in  order  to  produce  a  safe  and  satisfactory  design. 

95 


96  MILL  BUILDINGS 

ROOF   FRAMING. 

Before  undertaking  a  design  in  detail,  the  engineer  should  have 
a  general  knowledge  of  the  approximate  loads.  When  a  choice  has 
been  made  as  to  whether  the  building  shall  be  temporary  or  perma- 
nent, fireproof  or  otherwise,  the  weight  of  roof  framing  will  depend 
chiefly  upon  the  nature  of  the  roof  covering  and  the  presence  of 
cranes  or  trolleys  beneath  the  trusses.  The  capacity  of  cranes,  and 
the  kind  of  roof  covering,  should  be  determined  when  considering 
the  general  requirements. 

Table  XIII  gives  the  weight  per  square  foot  of  roof  surface  for 
various  kinds  of  roofing,  to  which  must  be  added  the  weight  of 
sheathing,  if  any,  and  from  2  to  4  pounds  per  square  foot  for  pur- 
lins, depending  upon  the  distance  between  trusses.  The  least 
weight  of  purlins  results  from  close  truss  spacing,  and  this  weight 
increases  with  the  distance  between  trusses.  The  usual  allowance 
for  combined  snow  and  wind  loads  is  20  to  30  pounds  per  square 
foot,  depending  on  the  latitude.  To  these  must  be  added  the  weight 
of  pipes,  shafting  or  trolleys  on  the  bottom  chords  and  the  weight 
of  trusses.  The  truss  weight  can  be  approximated  by  use  of  the 
eight  original  charts  shown  in  Figs.  110  to  117,  which  give  the 
total  weight  and  also  the  weight  per  square  foot  of  area  covered, 
for  trusses  of  four  different  types. 

Fig.  110*  gives  the  actual  weight  of  steel  roof  trusses  in  pounds, 
for  spans  varying  from  20  to  80  feet  in  length,  and  total  roof  loads 
of  40  pounds  per  horizontal  square  foot.  The  rafters  have  a  rise 
of  6  inches  per  foot,  known  as  one-quarter  pitch.  The  curves  show 
the  weight  of  trusses  for  spacings  of  10  to  20  feet  apart,  designed 
with  compression  and  tension  units  of  12,000  and  15,000  pounds 
per  square  inch,  respectively. 

Fig.  Ill*  shows  the  corresponding  weight  of  the  above  roof 
trusses  in  pounds  per  square  foot  of  area  covered. 

Fig.  112  gives  the  total  weight  of  steel  roof  trusses  in  pounds, 
for  spans  varying  from  30  to  80  feet,  with  the  same  rafter  slope 
and  unit  stresses  as  used  in  Fig.  110.  These  trusses  differ,  however, 
from  those  previously  described  by  having  a  lighter  capacity  of  only 
30  pounds  per  horizontal  square  foot  and  are  suitable  for  tropical 
countries  where  no  snow  falls. 

Fig.  113  gives  the  weight  of  steel  in  pounds  per  horizontal 
square  foot  for  the  trusses  referred  to  in  Fig.  112.  The  curves 
show  weights  for  truss  spacing  varying  from  10  to  18  feet.  If 

*  H.  G.  Tyrrell,  in  Engineering  News,  June  21,  1900. 


STATIC  EOOF  LOADS 


97 


weights  are  required  for  other  spacings,  they  may  be  found  approxi- 
mately by  drawing  corresponding  curves  on  the  weight  charts. 

Fig.  114  gives  the  total  weight  of  steel  roof  trusses  for  loads  of 
40  pounds  per  horizontal  square  foot  and  for  roof  slopes  of  4 
inches  per  foot.  These  weights  are  for  spans  varying  from  20  to 
GO  feet  in  length,  and  truss  spacings  of  8  to  16  feet  apart. 


Diagram  showing  Total  Weight  of  Roof  Trusses. 
Capacity  40  Ibs.  persg.  -ft-.  Horizon  fa/.   Pitch,  6  in.  per  -fh 
Units  l£,000  and  15,000  Ibs.  per  sg.  in. 


30 


3000 

rooo 

3000 
5000^ 

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£> 

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3000  £ 

EOOO 


1000 


woo 


40 


50  60  70 

Span    in     Feet. 

Fig.  110. 


80 


90 


Fig.  115  shows  the  corresponding  weight  in  pounds  per  horizon- 
tal square  foot  for  the  trusses  referred  to  in  Fig.  114. 

Fig.  116  is  chart  showing  the  total  weight  in  pounds  for  steel 
roof  trusses  with  a  capacity  of  45  pounds  per  square  foot,  and  a 
rafter  slope  of  one-half  inch  rise  per  foot.  These  trusses  are  suit- 
able for  roofs  with  plank  and  gravel  covering  on  longitudinal  pur- 


98 


MILL  BUILDINGS 


Weight  of  Poof  Trusses  per  sq.  ft-,  of  Area  Covered. 
Corporeity  40  Ibs.  per  sq.  ft-.       Pitch,    6  in.  per  ft. 
Units  )Z,000  and  15,000  Ibs. 
Weight  per  sq.  ft.  of  Area  Covered  =  5l^  +  £>;&£.  c. 

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Span       in       F«e-t. 

Fig.  111. 


Total  Weight  of  froof  Trusses. 
Capacity  30  Ibs.  per  scj.  -it.   Horizontal.  Pitch,  6  in   per  ft. 
Units   12,000  and  15,000  Ibs. 

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80 


90  100 


STATIC  HOOF  LOADS 


99 


lins.  As  purlins  are  used,  no  provision  is  made  in  the  top  chords 
for  resisting  bending  stresses. 

Fig.  1.17  gives  the  weight  of  steel  per  horizontal  square  foot  for 
the  roof  trusses  referred  to  in  Fig.  116. 

An  original  formula  by  the  author,  giving  the  weight  in  pounds 
per  horizontal  square  foot  for  the  trusses  referred  to  in  Fig.  110., 
is  as  follows: 

S  12 

W  =          -  +  • 

20  D 


Weight  of  Roof  Trusses, 
per  &q.  it  of  Area  covered,   Capacity  30  Jbs.  per  &q.  -ft. 
Pitch,   6  in.  per  fr.    Units  12,000  and  15,000  Jbs. 

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Fig.  113. 


Corresponding  formulas  for  the  weight  of  roof  trusses  given  by 
other  engineers  are  as  follows: 

Professor  Merriman's  formulae  for  trusses  in  spans  up  to  180 
feet  and  distances  apart  up  to  40  feet  are : 

For  steel  trusses W  =  %    (1  +  .IS) 

For   wood    trusses W  =  %    (1  +  -IS) 


Trautwine's  formula  is  as  follows : 

Total  weight  of  Fink  roof  trusses 
in  pounds 

Professor  Johnson's  formula  is : 


Square  of  span  in  feet 
3.1 


W  =  +  4 

25 


100 


MILL  BUILDINGS 


Formulae  by  C.  E.  Fowler  are: 

For  heavy   trusses W  =  .06  S  +  .6 

For  light  trusses W  =  .04  S  -f  -4 

Formula  by  Professor  N.  C.  Eicker : 

S  S2 


25 


6000 


In  all  the  foregoing  formulae— 

W  is  the  weight  of  steel  per  square  foot  of  area  covered; 

S,  the  span  in  feet,  arid 

D,  the  distance  in  feet — center  to  center  of  trusses. 


Total  Weight  of  Roof  Trusses. 
Capacity  40  Ibs.  per  sq.  it.   Horizontal. 
Pitch}4  In.  per  ft  Units  12,000  and  15,000  Ibs. 

30005 

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Fig.  114. 

Fig.  118  is  a  chart  showing  comparative  results  of  some  of  these 
formulae,  including  another  by  Professor  DuBois,  compared  with 
actual  truss  weights.  From  the  chart,  the  approximate  weight  of 
steel  roof  trusses  in  spans  up  to  130  feet  may  easily  be  found  by 
inspection. 

These  charts  are  for  definite  total  roof  loads  in  each  case,  but 
they  may  also  be  used  for  loading  of  a  lesser  or  greater  amount  by 
observing  the  following  directions.  The  weight  of  trusses  depends 
upon  the  total  load  per  lineal  foot  of  truss  carried.  Trusses  sup- 
porting a  40-pound  roof  load,  spaced  20  feet  apart,  sustain  the  same 
load  as  those  carrying  a  50-pound  load  and  spaced  only  16  feet 
apart.  Therefore,  if  it  is  desired  to  determine  the  weight  of  roof 
trusses  for  any '  other  roof  loading,  such  as  60  pounds  per 


STATIC  ROOF  LOADS 


Weight  of  Roof  Trusses, 
per  sq.  fr.  of  drear  covered.   Corporeity  4O  Ibs. 
per  sq.  fr.    Pitch  4-  in.  per  fr. 
r                Units  12,000  crnd   15,000  Ibs. 

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TotaJ    Weight   of  Steel   Trusses. 
Capacity  45  Ibs.  per  sq.  -ft.  HorizontcrJ.  Pitch,  ~  in.  per  ft. 

Units  l?,000  and  !5,000  Ibs, 
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Fig.  116. 


90 


1P3  MILL  BUILDINGS 

square  foot  spaced  12  feet  apart,  it  is  only  necesary  to  find  the 
total  load  per  lineal  foot  carried  by  the  truss,  which  in  this  case  is 
12  times  60,  or  720  pounds;  and  then  dividing  this  amount  by 
40,  the  corresponding  spacing  of  18  feet  is  found  for  the  40-pound 
trusses.  The  weight  of  60-pound  trusses  spaced  12  feet  apart  is 
therefore  the  same  as  the  weight  of  40-pound  trusses  spaced  18 
feet  apart.  These  weights  may  be  read  directly  from  the  charts, 
and  they  are  therefore  applicable  not  only  for  trusses  to  sustain 
the  loads  given  but  also  for  roof  loads  of  other  amounts  as  well. 


Weight  of  Roof  Trusses  per  sa.  it.  of  Area  covered- 
Capacity  45  Ibs.  per  sa.  ft.     Pitch,  *s  in.  per  fh 
Designed  for  Plank  and  OraveJ  Poof  on  Purlins. 

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80 


90 


Figs.  Ill,  113,  115  and  117,  for  the  weights  of  steel  roof  trusses 
in  pounds  per  square  foot  of  area  covered,  are  only  for  the  total 
roof  loads  given.  It  is  evident  that  if  the  total  load  per  square 
foot  supported  by  the  roof  is  increased,  the  corresponding  weight 
of  framing  per  square  foot  of  area  covered  will  also  be  increased. 
Figs.  Ill,  113,  .115  and  117  are  therefore  applicable  only  for  roof 
loads  as  given  on  each  chart.  For  loads  of  a  greater  or  less  amount, 
the  weights  per  square  foot  will  vary  nearly  in  direct  proportion, 
but  not  exactly,  for  it  is  not  always  possible  to  realize  the  required 
areas  in  all  the  members,  especially  in  the  smaller  ones.  For  exam- 
ple, if  it  is  required  to  find  the  weight  of  steel  per  square  foot  of 


STATIC  EOOF  LOADS 


103 


area  covered,,  in  roof  trusses  to  carry  a  total  roof  load  50  per  cent 
greater  than  given  on  the  chart,  or  60  pounds  per  square  foot,  the 
increased  weight  of  metal  would  be  about  45  per  cent,  or  somewhat 
less  than  the  proportion  of  increased  load. 

Comparing  two  trusses,  if  one  carries  twice  as  much  load  as 
the  other,  the  first  will  not  be  quite  twice  as  heavy  as  the  lighter 
one.  Fig.  *119  is  an  original  chart  from  which  the  weight  of  steel 
trusses  of  ordinary  slopes  may  be  determined  for  spans  of  any 


26,000 
24.000 
22,000 
20.000 
18,000 


Comparison  of  formulae  for 
Weight  of  Steel  Fink  Roof  Trusses. 

Load  40  Ibs.  persq.  ft   Pitch  6  ins.  in  IS  ins. 

Distance  on  Centers,  I0'o'l5'o"&  ZO'O" 

Trautwme'-s    Formula 

Merri man's        " 

Du  Bois '  "       -^^—^^^— 

Johnson's         »      - 

Actual  Weight    »      


14,000 


$000 


4000 


120      UO 


100      90       80       70       60       50      40 
Span      in      Feet. 

Fig.  118. 


30       £0       10 


length  and  loads  of  any  amount,  as  well  as  for  varying  unit  stresses. 
It  is  general  in  its  form,  and  is  suitable  for  all  spans  and  loads. 
The  diagrams  are  drawn  from  a  large  number  of  actual  cases  and 
are  therefore  correct. 

Loads  per  lineal  foot  include  both  dead  and  live  loads.  For 
concentrated  loads,  the  equivalent  uniform  load  may  be  used, 
remembering  that  a  concentrated  load  at  the  center  of  a  span  pro- 
duces bending  moments  that  are  twice  as  great  as  when  the  same 
load  is  distributed  uniformly  over  the  entire  length. 

To  illustrate  the  use  of  this  chart,  suppose  that  ,it  is  required 
to  find  the  weight  of  a  steel  roof  truss  of  80-foot  span,  to  carry  a 


106  MILL  BUILDINGS 

Corrugated  iron,  painted  or  galvanized,  No.  22 1.6 

Corrugated  iron,  painted  or  galvanized,  No.  20 1.9 

Corrugated  iron,  painted  or  galvanized,  No.  18 2.6 

Corrugated  iron,  painted  or  galvanized,  No.  16 3.3 

Copper  roofing  in  Sheets 1.5 

Copper  roofing  in  tiles 1.75 

Shingles,  common 2.5 

Shingles,  18  in 3.0 

Felt  and  gravel  roofing,  four-ply 5.5 

Felt  and  gravel  roofing,  five-ply 6.0 

Slate,  Vs   in.  thick 5.0 

Slate,  3/16  in.  thick,    6x12  ins 7.25 

Slate,  3/16  in.  thick,  12x24  ins 8.25 

Slate,  %  in.  thick 9.6 

Tiles,  Eoman,  in  one  part 8.0 

Tiles,  Roman,  in  two  parts 12.0 

Tiles,  Spanish,  in  one  part 8.0 

Tiles,  Spanish,  in  two  parts 19.0 

Tiles,  Ludowici 8.0 

Extra,  if  tiles  are  laid  in  mortar 10.0 

Skylight  with  %  in.  glass 4.5 

Skylight  with  5/16  in.  glass 5.0 

Skylight  with  %  in.  glass 6.0 

Wood  sheathing,  white  pine  or  spruce 3.0 

Wood  sheathing,  southern  pine 4.0 

Wood  sheathing,  chestnut  or  maple 4.0 

Wood  sheathing,  ash  or  oak 5.0 

Wood  rafters  and  purlins 7.0 

Reinforced  concrete  slabs,  per  inch  thickness 13.0 

TABLE  XIV. 

The  total  loads  per  square  foot  of  roof  surface  for  different 
kinds  of  roofing,  including  framing,  is  as  follows : 

Eoof  Covering.  Lbs.  per  sq.  ft. 

Corrugated  iron,  unboarded     * 8  to  10 

Corrugated  iron,  on  boards    10  to  12 

Slate  on  laths   12  to  15 

Slate  on  1%   in.  boards 15  to  18 

Tar  and  gravel 10  to  12 

Shingles  on  laths 8  to  10 

Tile  on  plank 20  to  30 

Tile  laid  in  mortar 25  to  35 

Sheet  metal  on  boards 7  to    9 

3  in.  reinforced  concrete 40  to  45 


CHAPTER  XI. 

FLOOR  LOADS. 

Building  laws  of  various  cities,  for  the  purpose  of  regulating 
the  strength  of  floors,  specify  the  minimum  safe  loads  for  which 
they  shall  be  proportioned  (Table  XV).  These  -  laws,  however, 
apply  more  to  buildings  which  are  subject  to  regular  classification 
than  to  mills  and  factories.  The  loads  in  such  buildings  must  be 
determined  separately,  and  the  floors  proportioned  in  each  case  to 
sustain  them.  For  such  buildings  as  foundries,  the  charging  plat- 
forms may  be  subjected  to  1,000  pounds  per  square  foot  or  more, 
while  floors  for  light  manufacturing  may  have  no  greater  than 
200  to  300  pounds  per  square  foot.  The  necessity  is  therefore 
evident,  for  investigating  the  requirements  of  each  case  -by  itself 
and  proportioning  the  framing  accordingly. 

The  following  weight  tables  are  given  for  the  purpose  of  esti- 
mating these  imposed  loads.  Table  XVI  gives  the  weight  per 
cubic  foot  of  various  kinds  of  building  materials,  and  also 
the  weight  of  manufactured  materials  and  merchandise.  By  the 
use  of  these  tables  the  approximate  amount  of  imposed  loads  can 
be  estimated.  To  these  must  be  added  the  weight  of  the  floors, 
which  can  be  computed  after  the  general  type  has  been  determined. 

Green  timber  weighs  from  20  to  50  per  cent  more  than  the 
weights  given  in  the  table,  which  are  for  dry  woods. 

If  partitions  occur,  the  weight  of  these  must  also  be  added  to 
the  total  loads.  Ordinary  stud  partitions,  plastered  on  both  sides, 
weigh  about  20  pounds  per  square  foot. 

TABLE  XV. 

MINIMUM  SAFE   IMPOSED   LOADS  ON   FLOORS,  ACCORDING  TO 
BUILDING  LAWS  OF  VARIOUS   CITIES. 

Minimum  live  loads  on  floors  in  pounds  per  square  foot. 

New  Chi-  Phila-  St. 

Kind  of  building.                 Yor~k.  cago.  delphia.  Boston.    Louis.  Buffalo. 

Dwellings 60  70  ...  50  70             40 

Apartments,    hotels 60  50  70  50  70             70 

Office  buildings,  1st  floor ..    150  100  100  100  150             70 

Office  buildings,  upper  floor     75  100  100  100  70 

Stables  or  carriage  houses.      75  40-100 

Public  assembly  halls 90  100  120  150  120           100 

Light  man 'f'g  and  storage  120  100  120  ...  ...            120 

Storehouse  for  heavy  mate- 
rials; warehouses  or  fac- 
tories    150  ...  150  250  

107 


106  MILL  BUILDINGS 

Corrugated  iron,  painted  or  galvanized,  No.  22 1.6 

Corrugated  iron,  painted  or  galvanized,  No.  20 1.9 

Corrugated  iron,  painted  or  galvanized,  No.  18 2.6 

Corrugated  iron,  painted  or  galvanized,  No.  16 3.3 

Copper  roofing  in  Sheets 1.5 

Copper  roofing  in  tiles 1.75 

Shingles,  common 2.5 

Shingles,  18  in 3.0 

Felt  and  gravel  roofing,  four-ply 5.5 

Felt  and  gravel  roofing,  five-ply 6.0 

Slate,  Vs   in.  thick 5.0 

Slate,  3/16  in.  thick,    6x12  ins 7.25 

Slate,  3/16  in.  thick,  12x24  ins 8.25 

Slate,  %  in.  thick 9.6 

Tiles,  Koman,  in  one  part 8.0 

Tiles,  Roman,  in  two  parts 12.0 

Tiles,  Spanish,  in  one  part 8.0 

Tiles,  Spanish,  in  two  parts 19.0 

Tiles,  Ludowici 8.0 

Extra,  if  tiles  are  laid  in  mortar 10.0 

Skylight  with  %  in.  glass 4.5 

Skylight  with  5/16  in.  glass 5.0 

Skylight  with  %  in.  glass 6.0 

Wood  sheathing,  white  pine  or  spruce 3.0 

Wood  sheathing,  southern  pine 4.0 

Wood  sheathing,  chestnut  or  maple 4.0 

Wood  sheathing,  ash  or  oak 5.0 

Wood  rafters  and  purlins 7.0 

Reinforced  concrete  slabs,  per  inch  thickness. 13.0 

TABLE  XIV. 

The  total  loads  per  square  foot  of  roof  surface  for  different 
kinds  of  roofing,  including  framing,  is  as  follows : 

Roof  Covering.  Lbs.  per  sq.  ft. 

Corrugated  iron,  unbearded     * 8  to  10 

Corrugated  iron,  on  boards    10  to  12 

Slate  on  laths   12  to  15 

Slate  on  1^4   in.  boards 15  to  18 

Tar  and  gravel 10  to  12 

Shingles  on  laths 8  to  10 

Tile  on  plank 20  to  30 

Tile  laid  in  mortar 25  to  35 

Sheet  metal  on  boards 7  to    9 

3  in.  reinforced  concrete 40  to  45 


CHAPTER  XI. 

FLOOR  LOADS. 

Building  laws  of  various  cities,  for  the  purpose  of  regulating 
the  strength  of  floors,  specify  the  minimum  safe  loads  for  which 
they  shall  be  proportioned  (Table  XV).  These  -  laws,  however, 
apply  more  to  buildings  which  are  subject  to  regular  classification 
than  to  mills  and  factories.  The  loads  in  such  buildings  must  be 
determined  separately,  and  the  floors  proportioned  in  each  case  to 
sustain  them.  For  such  buildings  as  foundries,  the  charging  plat- 
forms may  be  subjected  to  1,000  pounds  per  square  foot  or  more, 
while  floors  for  light  manufacturing  may  have  no  greater  than 
200  to  300  pounds  per  square  foot.  The  necessity  is  therefore 
evident,  for  investigating  the  requirements  of  each  case  -by  itself 
and  proportioning  the  framing  accordingly. 

The  following  weight  tables  are  given  for  the  purpose  of  esti- 
mating these  imposed  loads.  Table  XVI  gives  the  weight  per 
cubic  foot  of  various  kinds  of  building  materials,  and  also 
the  weight  of  manufactured  materials  and  merchandise.  By  the 
use  of  these  tables  the  approximate  amount  of  imposed  loads  can 
be  estimated.  To  these  must  be  added  the  weight  of  the  floors, 
which  can  be  computed  after  the  general  type  has  been  determined. 

Green  timber  weighs  from  20  to  50  per  cent  more  than  the 
weights  given  in  the  table,  which  are  for  dry  woods. 

If  partitions  occur,  the  weight  of  these  must  also  be  added  to 
the  total  loads.  Ordinary  stud  partitions,  plastered  on  both  sides, 
weigh  about  20  pounds  per  square  foot. 

TABLE  XV. 

MINIMUM  SAFE   IMPOSED  LOADS  ON   FLOORS,  ACCORDING  TO 
BUILDING  LAWS  OF  VARIOUS   CITIES. 

Minimum  live  loads  on  floors  in  pounds  per  square  foot. 

New  Chi-  Phila-  St. 

Kind  of  building.                 York.  cago.  delphia.  Boston.    Louis.  Buffalo. 

Dwellings 60  70  ...  50  70             40 

Apartments,    hotels 60  50  70  50  70             70 

Office  buildings,  1st  floor ..    150  100  100  100  150             70 

Office  buildings,  upper  floor     75  100  100  100  70 

Stables  or  carriage  houses.      75  40-100 

Public  assembly  halls 90  100  120  150  120           100 

Light  man 'f'g  and  storage  120  100  120  ...  ...            120 

Storehouse  for  heavy  mate- 
rials; warehouses  or  fac- 
tories    150  ...  150  250 

107 


108  MILL  BUILDINGS 

TABLE  XVI. 

WEIGHT  OF  BUILDING  MATEEIAL. 

Seasoned  woods —  Weight  per  cu.  ft. 

Ash 38 

Cherry    43 

Chestnut     41 

Cypress   64 

Elm 35 

Hemlock    25 

Hickory    53 

Mahogany,  Spanish 53 

Mahogany,    Honduras    35 

Maple    49 

Oak,  live 59 

Oak,  white   52 

Pine,  white    25 

Pine,  yellow,  northern 34 

Pine,  yellow,  southern 45 

Poplar  29 

Spruce 25 

Sycamore    37 

Walnut,   black 38 

Brick  and  stone — 

Brick,   best   pressed 150 

Brick,  common,  hard 125 

Brick,    soft,    inferior 100 

Cement,   Eosendale 56 

Cement,    Louisville 50 

Cement,   English   Portland 90 

Granite,    solid 170 

Granite,  broken , 96 

Limestone,   solid 168 

Limestone,    broken 100 

Quartz     ' 165 

Sandstone   150 

Shales,  red  and  black 165 

Slate    175 

Gravel  and  sand 90  to  130 

Masonry — 

Brickwork,   pressed   brick 140 

Brickwork,  ordinary 112 

Stone    concrete 140 

Cinder    concrete     95 

Granite  or  limestone,  dressed 165 

Granite    or    limestone,    rubble 154 

Granite  or  limestone,  dry 138 

Sandstone,  dressed   144 

WEIGHT  OF  MEECHANDISE. 

Lbs.  per  cu.  ft. 

Alcohol    50  to  57 

Aluminum     162 

Asphaltum    

Alum   33 

Brass     510 

Bronze     520 

Boxwood   60 

Bleaching  Powder 31 

Calcite 170 

Chalk     156 

Charcoal   15  to    30 

Coal,  anthracite 81  to  106 


FLOOR  LOADS  109 

Coal,  anthracite,  piled  loose 47  to    58 

Coal,    bituminous 78  to    88 

Coal,  bituminous,  piled  loose 44  to    54 

Coke    23  to    32 

Copper 540 

Cork     16 

Cotton  goods   11  to    33 

Carpet 12 

Corn 31 

Corn   Meal    37 

Cutch     45 

Caustic    Soda    88 

Crockery    40 

Cheese     30 

Clay,    potters    100  to  140 

Clay,   in  lumps 65 

Earth,  common  loam,  dry 72  to    80 

Earth,    soft    flowing 100  to  110 

Flour    40 

Glass     160 

Glassware  in  boxes 60 

Gypsum     142 

Gypsum,  in  lumps 82 

Gypsum,   ground,   loose 56 

Gutta    percha 61 

Hay,  baled 24 

Iron 450 

Ice     57 

India   rubber 58 

Indigo     43 

Oats     27 

Oils   54  to    57 

Lead    710 

Lard  Oil 34 

Lime    50 

Leather  in  bales 16  to    23 

Petroleum     55 

Pitch     72 

Plaster    53 

Paper,  strawboard  newspaper 33  to    44 

Paper,   calendered   book 50  to    70 

Paper,  writing  and  wrapping 70  to    90 

Eosin     69 

Rope 42 

Rags  in  bales   15  to    36 

Salt   50  to    70 

Snow,  fresh  fallen  and  light 5  to    12 

Snow,  packed  and  heavy 15  to    50 

Steel    490 

Sulphur     125 

Sugar    42 

Starch    23 

Soda    Ash 62 

Silk     8  to    32 

Sumac     39 

Tallow 58 

Tar    62 

Tin    459 

Tobacco 28 

Wool  in  bales   15  to    22 

Woolen  goods   13  to    22 

Wheat 39  to    44 

Water    62 


CHAPTER  XII. 

SNOW  AND  WIND  LOADS. 

Table  XVII  and  the  chart  in  Fig.  121  show  the  amount  of 
snow  loads  that  will  occur  in  different  latitudes  of  North  America 
for  roofs  of  various  pitches. 

Light  snow  will  weigh  from  5  to  10  pounds  per  cubic  foot,  while 
heavy  snow  that  is  packed  may  weigh  40  to  50  pounds.  While 
snow  in  Manitoba,  Minnesota,  Quebec  and  Maine  frequently 


Snow  Loads    in   Ibs    per  scf.   -ft.    of  Roof 
Surface,    for  Various    Roof  Pitches   and   Latitudes. 

4= 
50^ 

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25  30  35  40  45 

Latitude    in     Degrees. 

Fig.  121. 


50 


55 


falls  to  a  depth  of  4  to  6  feet,  or  even  more,  it  does  not  lie  to 
this  depth  on  exposed  surfaces  such  as  roofs,  and  a  maximum 
snow  load  of  42  pounds  per  horizontal  square  foot  is  therefore  safe 
for  50  degrees  north  latitude.  In  addition  to  roofs  being  in  exposed 
positions,  they  frequently  have  considerable  slope,  so  that  the  snow 
will  slide  from  its  own  weight.  Snow  will  not  remain  on  roof 

110 


SNOW  AND  WIND  LOADS  HI 

slopes  exceeding  45  degrees,  or  half  pitch,  and  there  will  conse- 
quently be  no  snow  load. 

Even  on  comparatively  flat  roofs,  there  are  certain  locations  so 
exposed  to  wind  that  the  probability  of  large  snow  loads  is  com- 
paratively small.  Therefore,  in  making  allowance  for  snow,  judg- 
ment must  be  used.  Snow  conditions  in  the  mountain  states  and 
high  altitudes  are  different  from  those  at  lower  levels,  and  these 
conditions  may  also  be  affected  by  the  amount  of  precipitation, 
which  is  less  in  the  arid  states  than  near  the  sea  coast. 

The  general  rule  for  the  northern  part  of  the  United  States  is 
to  provide  for  snow  loads  to  the  extent  of  from  10  to  20  pounds 
per  square  foot,  on  pitches  of  1/4  or  1/5.  For  the  latitude  of 
Chicago  or  New  York,  20  pounds  will  ordinarily  be  ample.  The 
snow  loads  given  in  the  table  and  chart  above  are  per  square  foot 
of  exposed  roof  surface,  but  it  will  be  noted  that  the  weight  itself 
acts  vertically. 

In  designing  the  Sayer  shops,  which  are  covered  with  a  3-inch 
reinforced  concrete  slab,  the  ordinary  pitch  roofs  were  proportioned 
for  a  total  load  of  75  pounds  per  square  foot,  while  the  saw  tooth 
roof  was  figured  for  a  total  load  of  85  pounds  to  provide  for  the 
extra  snow. 

TABLE  XVII. 

SNOW    LOADS    IN    LBS.    PEE    SQ.    FT.    OF    KOOF    SUPFACE    FOE 
VARIOUS   PITCHES   AND   LATITUDES. 

Lati-  ys  V*  %  1/6  Pitch 

tude.  Pitch.  Pitch.  Pitch.  or  less. 

New   Orleans    30  4  5  7  8 

Memphis    35  7  10  13  16 

Cincinnati    40  10  15  20  24 

St.   Paul    45  13  20  26  33 

Winnipeg 50  17  25  33  42 

TABLE  XVIII. 
WIND  VELOCITIES  AND  COREESPONDING  PRESSURES. 

— Velocity Pressure — 

Miles  Per  Hr.  Lbs.  Per  Sq.  Ft. 

Just   perceptible 2  .02 

Gentle   breeze    5  .12 

Pleasant    10  .50 

Brisk  gale    20  1.90 

High  wind   30  4.40 

Very    high    wind 40  7.80 

Storm    50  12.30 

Violent  storm    60  17.70 

Hurricane  80  31.40 

Violent    hurricane    .                                                       100  49.00 


MILL  BUILDINGS 

TABLE  XIX. 

WIND     COEFFICIENTS     FOE     VARYING     ROOF     P.JTCHES     AND 
WIND   PRESSURES. 

Angle  of  Boof.  5°  10°  20°  30°  40°  50°  60°  70°  80°  90° 

N  =  F  X   .125  .24  .45  .66  .83  .95  1.00  1.02  1.01  10 

V  =  F  X   .122  .24  .42  .57  .64  .61  .50  .35  .17  .0 

H  =  F  X   .01  .04  .15  .33  .53  .73  .85  .96  .99  1.0 

In  the  above — 

A  =  angle  of  roof  surface  with  horizontal. 

F  =  force  of  wind  in  pounds  per  square  foot. 

N  —  pressure  normal  to  roof  surface. 

V  =  pressure  perpendicular  to  direction  of  wind. 

H  =  Pressure  parallel  to  direction  of  wind. 

For  wind  pressure  of  30  pounds  per  square  foot  against  a  ver- 
tical surface,  normal  wind  pressures  on  roofs  of  varying  slopes  may 
be  obtained  by  use  of  the  coefficients  given  in  Table  XIX.  These 
normal  wind  pressures  are  given  in  Table  XX. 

TABLE  XX. 

NORMAL  WIND  PRESSURE  ON  ROOFS  OF  VARIOUS  SLOPES  FOR 

A   HORIZONTAL  WIND   PRESSURE   OF   30   LBS.   PER   SQ.    FT. 

AGAINST  A  VERTICAL  SURFACE. 

Pressure 
Angle.  Lbs.  Per  Sq.  Ft. 

5°    3.9 

10°    7.2 

15°    10.5 

18°-26'    (1/6    pitch) 13. 

20°    13.7 

21°-48'    (y5    pitch) 15. 

25°    16.9 

26°-34'    (1,4    pitch) 18. 

30°    19.9 

33°-41'   (1/3  pitch) 22. 

35°   22.6 

40° 25.1 

45°    (1/2  pitch) 27.1 

50°    . 28.6 

55°    29.7 

60°    30. 

Table  XX  from  Mill  Building  Construction,  by  H.  G.  Tyrrell. 

WIND  LOADS. 

The  result  of  wind  action  on  buildings  can  only  be  approxi- 
mated. Experiments  to  ascertain  the  force  of  wind  for  various 
velocities  show  that  the  greatest  wind  pressures  during  violent  hurri- 
canes amount  to  40  to  50  pounds  per  square  foot.  It  is 
impracticable  to  proportion  ordinary  buildings  to  resist  the  pres- 
sures of  tornadoes  or  hurricanes,  for  if  the  building  were  not  de- 


SNOW  AND  WIND  LOADS  113 

stroyed  by  the  wind,  it  probably  would  be  from  flying  wreckage 
and  materials.  It  is  sufficient,  excepting,  perhaps,  in  very  exposed 
positions,  such  as  unsheltered  points  on  stormy  coasts,  to  propor- 
tion buildings  to  resist  a.  wind  pressure  of  30  pounds  per  square  foot 
of  vertical  surface. 

Table  XVIII  gives  the  wind  pressures  on  vertical  surfaces,  for 
velocities  varying  from  two  to  one  hundred  miles  per  hour.  A 
pressure  of  30  pounds  per  square  foot  corresponds  with  a  wind 
velocity  of  80  miles  per  hour. 

Table  XIX  gives  wind  coefficients  for  roof  pitches  varying  from 
5  to  90  degrees  with  the  horizontal. 

Table  XXI  gives  combined  snow  and  wind  loads  for  roofs  of 
different  pitches  in  northern  latitudes.  Roofs  should  never  be  pro- 
portioned for  a  less  combined  snow  and  wind  load  than  25  pounds 
per  square  foot  of  roof  surface.  Wind  is  more  severe  when  acting 
on  surfaces  in  exposed  positions  high  above  ground  than  on  lower 
buildings.  It  is,  therefore,  good  practice  to  proportion  building 
frames  that  are  60  feet  in  height  or  more  for  a  horizontal  pressure 
of  30  pounds  per  vertical  square  foot,  or  20  pounds  per  square  foot 
for  heights  of  25  feet  or  less.  Between  these  limits  of  25  and  60 
feet,  wind  pressures  should  be  assumed  from  20  to  30  pounds, 
depending  on  the  height.  In  all  cases  the  action  of  wind  is  consid- 
ered normal  to  the  plane  of  the  roof  or  surface. 

The  overturning  effect  on  a  building  as  a  whole  need  be  con- 
sidered only  for  high,  narrow  buildings,  but  the  increased  stress 
in  the  leaward  columns  must  be  considered.  No  side  girths  should 
have  provision  for  a  less  pressure  than  20  pounds  per  square  foot 
of  wall. 

TABLE  XXI. 

ALLOWANCE  FOR  WIND  AND  SNOW,  COMBINED,  IN  LBS.,  PER 
SQ.  FT.  OF  ROOF  SURFACE. 

Pitch  of  Eoof. 

Location.  60°  45°  if,  *4  %  % 

Northwest  States 30  30  25  30  37  45 

New   England   States 30  30  25  25  35  40 

Rocky  Mountain  States 30  30  25  25  27  35 

Central  States    30  30  25  25  22  30 

Southern  Pacific  States..  30  30  25  25  22  20 


CHAPTER  XIII. 

t 

CKANE  AND  MISCELLANEOUS  LOADS. 

The  load  on  each  of  the  two  end  wheels  of  small  shop  traveling 
cranes  is  approximately  equal  to  the  capacity  of  the  crane  when  the 
fully  loaded  trolley  is  at  that  end.  The  load  at  the  other  end  will 
then  be  proportionately  less.  Tables  XXII  and  XXIII  give  in 
detail  loads  on  crane  girders  from  traveling  cranes,  Table  XXIII 
being  for  hand  cranes,  while  Table  XXII  is  for  electric  traveling 
cranes.  + 

The  necessary  capacity  of  cranes  having  been  decided  to  prop- 
erly serve  the  shop  needs,  the  framing  for  the  crane  system  can  be 
proportioned  by  use  of  the  load  tables  given.  No  feature  of  a 
modern  shop  is  of  greater  importance  than  its  appliances  for 
handling  and  moving  materials,  for  upon  these  much  of  the  shop 
efficiency  depends.  In  many  cases  and  especially  for  light  loads, 
pneumatic  or  electric  hoists  with  their  rapid  operation,  are  the 
most  convenient. 

Jib  cranes  are  too  various  in  arrangement  and  design  to  admit 
of  any  satisfactory  tabulation.  The  principal  stresses  in  the  frame- 
work will  occur  in  the  bottom  chord  bracing  and  the  knee  braces 
joining  the  trusses  to  columns.  Traveling  jib  cranes,  wrhich  are 
now  very  generally  used,  will  also  cause  heavy  stresses  in  the  frame- 
work and  must  be  carefully  provided  for,  as  there  is  no  class  of 
stress  to  which  manufacturing  buildings  are  subjected,  so  severe 
on  the  building  as  is  the  action  of  traveling  cranes.  The  action  of 
cranes  is  constant  and  continuous,  while  high  winds  or  snow  loads 
may  seldom  occur. 

The  loads  on  trolley  beams  suspended  from  the  trusses  will 
cause  stresses,  the  amount  of  whjch  will  depend  directly  upon  the 
weight  lifted  and  the  weight  of  trolley  and  hoisting  block. 

All  crane  loads  referred  to  and  tabulated  include  the  weight  of 
the  materials  lifted  and  the  dead  weight  of  the  crane,  with  trolley 
and  machinery,  but  they  do  not  include  the  weight  of  the  support- 
ing crane  system,  such  as  crane  girders  or  columns.  In  proportion- 
ing crane  girders,  their  dead  weight  and  the  weight  of  track  rail 
must  be  added  to  the  weights  tabulated. 

114 


CEANE  AND  MISCELLANEOUS  LOADS 


115 


TABLE  XXII. 

*MAXIMUM   LOAD    IN   LBS.    ON   EACH   OF   TWO    END    WHEELS. 
ELECTRIC  TRAVELING  CRANES. 


Capacity  — 30 — 

in  Tons.  Load.  D. 

3y2.' 9300     8 

5     11600  10 

7V2 14900  11 

10     18500  11 

15     25000  12 

20     31000  12 

25     37000 

30     43000 

40     57000 

50  .  70000 


Span  in  Ft. 


—40  — 
Load.  D. 
10200  9 
12800  10 
16200  11 
19800  11 
26500  12 
32700  12 
39300  12 
46200  13 
60100  14 
74000  13 

—50— 
Load.  D. 
11300  10 
14100  10 
17600  10 
21200  11 
28100  12 
34600  12 
41800  12 
48800  13 
63400  14 
77600  13 

—  60— 
Load.  D. 
12600  10 
15500  11 
19100  10 
22700  11 
29800  12 
37000  12 
44500  13 
51700  13 
67000  13 
82000 

—  70— 
Load.  D. 
14300  12 
17100  12 
20800  12 
24500  12 
31800  12 
39700  12 
47500  12 
55000  13 
71000  13 
86600 

—80— 
Load.  D. 
16000  13 
18900  13 
22700  13 
26800  13 
34300  13 
42800  13 
50800  13 
58800  13 
75600  13 
90000 

TABLE  XXIII. 


'MAXIMUM    LOAD   IN   LBS.    ON   EACH    OF   TWO    END    WHEELS, 
HAND  TRAVELING  CRANES. 


Capacity       — 20 — 
in  Tons.    Load.  D, 


2900 

5000 

7500 

10000 


D. 

4 
4 

6 
6 
6 
6 

7 
7 
7 
is 

—  30— 
Load.  D. 
3100  4 
5400  4 
8000  6 
10500  6 
13000  7 
15600  7 
20700  7 
26000  7 
32300  7 
the  distance 

Span  of  Crane  in  Ft. 

Load.  D.  Load.  D. 
3500  5 
5800  5   6400  5 

8600  7   9200  7 
11100  7  11800  7 
13600  7  14300  8 
16300  7  17100  8 
21400  8  22300  8 
27000  8  28000  8 
33500  8  34800  8 
apart  in  feet  of  two 

—60— 
Load.  D. 

10000  8 
12600  8 
15300  8 
18100  8 
23400  9 
29300  9 
36200  9 
end  crane 

—  70— 
Load.  D. 

10700  8 
13400  8 
16100  9 
19100  9 
24600  9- 
30700  9 
38000  9 
wheels. 

10 12400 

12 15000 

16 20000 

20 25100 

25 31100 

Dimension  D  is 

Addition  must  be  made  to  crane  loads  to  provide  for  the  effect 
of  impact,  and  this  should  be  from  25  to  50  per  cent,  depending 
upon  the  severity  of  the  crane  service.  It  is  the  practice  of  some 
designers  to  neglect  the  impact  addition  and  to  use  lower  unit 
stresses  for  the  crane  system  than  for  the  other  parts  of  the  build- 
ing; but  a  more  scientific  method  of  design  is  to  consider  and 
include  all  loads,  and  use  tension  units  approaching  one-half  the 
elastic  limit. 

In  the  Tables  XXII  and  XXIII  above,  the  dimension  D  is  the 
distance  in  feet  between  the  two  wheels  at  either, end  of  the  crane. 
It  will  be  noted  that  the  loads  given  are  the  loads  on  each  wheel. 
It  may  sometimes  be  desirable  to  make  two  or  more  roof  trusses  at 
either  end,  sufficiently  strong  to  permit  the  crane  bridge  to  be 
lifted  from  its  track  by  pulleys  attached  to  the  trusses.  This  pro- 
vision would  avoid  the  need  of  temporary  staging,  and  the  extra 
expense  might  be  warranted. 


*  From  Mill  Building  Construction,  by  H.  G.  Tyrrell. 


MILL  BUILDINGS 

MISCELLANEOUS  LOADS. 

There  are  numerous  other  loads  which  do  not  permit  of  any  sys- 
tematic arrangement  or  tabulation,  but  which  may  exist.  It  is  some- 
times convenient  to  provide  trolleys  running  directly  on  the  bottom 
truss  chords,  or  provision  may  be  desired  for  attaching  pulley  blocks, 
for  raising  light  wei  Jhts,  to  the  bottom  chords  at  any  point.  Steam 
pipes,  heating  ducts  and  shafting  often  add  much  to  the  load,  and 
occasionally  a  plank  walk  is  placed  in  the  trusses  for  the  purpose  of 
reaching  the  ventilator  windows,  for  making  inspection  and  repairs, 
or  oiling  the  shafting.  Otrfcr  items  which  may  increase  the  roof 
loads  are  circular  metal  ventilators,  skylights,  sash  operating  ma- 
chinery, shutters,  etc.,  provision  for  all  of  which  should  be  liberal. 
Columns  in  exposed  positions  may  be  subject  to  jars  or  blows  from 
passing  vehicles  or  materials,  and  their  strength  must  be  increased 
accordingly.  Other  loads,  such  as  the  pull  from  belts  and  the  gen- 
eral effect  of  vibration  from  rapidly  moving  machinery,  should  also 
have  ample  provision.  It  is  the  practice  of  some  designers  to  make 
a  general  addition  to  the  loads  of  from  5  to  10  pounds  per  square 
foot  over  the  entire  truss  area,  to  cover  the  effect  of  vibration. 

It  is  convenient  in  shops  with  electric  power  to  place  motors 
above  the  floor  and  thereby  save  useful  floor  space.  If  they  are 
set  on  platforms  between  the  roof  trusses,  provision  must  be  made 
for  this  extra  load.  It  should  be  noted,  however,  that  all  the  above 
loads  may  not  always  occur  at  the  same  time,  and  provision  need 
not  be  made  for  them  all  combined. 

SUMMAEY  OF  LOADS. 

The  weight  of  framing  in  ordinary  mill  roofs  varies  generally 
from  4  to  7  pounds  per  square  foot  of  ground  area.  Adding  to  this 
the  weight  of  roof  covering,  gives  the  combined  weight  of  framing 
and  covering,  according  to  Table  XIV,  page  106. 

These  weights  are  for  roofs  with  spans  up  to  about  75  feet.  For 
spans  of  100  feet,  add  3  pounds  per  square  foot  to  the  above  and 
proportionally  between.  If  roofs  are  ceiled  and  plastered,  add  10 
pounds  per  square  foot  for  the  lath  and  plaster  only,  and  additional 
weight  for  the  ceiling  joist. 

For  combined  snow  and  wind  in  northern  latitudes  of  the 
United  States,  add  from  25  to  35  pounds  per  square  foot  of  roof 
surface  as  given  in  detail  in  Table  XXI. 

No  roof,  even  where  snow  does  not  fall,  should  be  proportioned 
for  a  less  load  than  30  pounds  per  square  foot,  and  no  purlins  for 
less  than  25  pounds  per  square  foot. 


CRANE  AND  MISCELLANEOUS  LOADS 

The  weight  of  steel  framing  on  sides  of  buildings  consisting  of 
steel  columns  and  girths  covered  with  corrugated  iron,  is  from  4 
to  6  pounds  per  square  foot  of  exposed  surface,  for  the  framing 
only. 

An  approximate  rule  for  the  extra  weight  of  steel  in  the  sup- 
porting systems  of  traveling  cranes  is  that  for  every  5  tons'  capacity 
of  crane  there  will  be  about  100  pounds  of  extra  steel  per  lineal 
foot  of  building  in  the  two  side  girder  and  crane  columns. 


PART  III 
FRAMING 


CHAPTER  XIV. 

STEEL  FRAMING. 

All  the  general  features  of  a  building,  with  its  size,  shape  and 
dimensions,  must  be  determined  as  described  in  Part  I,  before  start- 
ing the  framing  plans.  The  arrangement  and  location  of  machinery, 
inside  height  and  clearance,  kind  and  capacity  of  cranes,  kind  of 
building  material,  size  and  weight  of  contents,  with  the  methods  of 
lighting,  heating,  ventilating  and  draining,  must  all  be  considered, 
preliminary  to  laying  out  the  framing  plans  or  computing  the  sizes. 
The  number  of  columns  and  the  clear  space  between  them,  the  roof 
pitch,  amount  and  kind  of  skylights,  number  and  width  of  moni- 
tors, must  all  be  fixed  before  undertaking  the  work  outlined  in  this 
chapter.  The  building  must  be  rigid,  large  enough  for  its  equip- 
ment and  occupants,  and  suited  to  the  work  to  be  done  therein. 
Before  detail  plans  are  made,  the  preliminary  considerations  should 
be  reviewed,  and  the  general  arrangement  verified,  so  expensive 
alterations  will  not  result. 

The  framing  should  be  studied  out  on  small  sheets  of  paper, 
preferably  not  larger  than  cap  size,  8J  by  13  inches,  single  lines 
being  used  to  indicate  members  (Fig.  32).  From  these  small 
sketches,  J-inch  scale  details  may  be  made,  and  a  show  drawing 
prepared. 

The  design  for  each  building  should  be  developed  according  to 
its  special  requirements,  and  for  the  roof  framing  should  begin  with 
the  kind  of  covering  and  the  method  of  supporting  it.  The  spacing 
of  rafters  or  purlins  will  depend  on  the  supporting  strength  of  the 
plank  or  slab,  and  the  relative  arrangement  of  parts  must  be  pro- 
portioned to  each  other.  Pieces  must  be  included  in  the  design 
only  when  they  have  a  definite  purpose,  and  not  merely  to  copy 
other  designs  or  to  follow  usual  methods. 

119 


120  MILL  BUILDINGS 

BUILDING  FRAMES. 

The  frames  of  mill  and  manufacturing  buildings  are  a  combina- 
tion of  trusses,  monitors,  rafters,  purlins,  columns  and  girders, 
properly  braced  together,  to  form  a  shelter  and  enclosure,  and  sup- 
port for  cranes  and  machinery.  Framing  may  consist  of  single-span 
roofs  resting  on  side  walls  or  columns  in  the  walls,  or  may  have  one 
or  more  lines  of  interior  columns  to  support  the  roof  and  crane 
tracks,  with  or  without  intermediate  floors  or  galleries.  The  outline 
of  the  building,  and  all  its  general  features,  will  be  selected  accord- 
ing to  the  principles  explained  in  Part  I. 

Figs.  122  to  161  show  a  variety  of  building  frames,  the  first 
thirteen  having  a  single  line  of  interior  columns,  while  the  remain- 
ing ones  have  two  lines.  Figs.  130  to  133  have  monitor  frames 
over  the  center  line  of  columns,  with  clear  open  space  beneath  them. 
Fig  134  is  a  simple  flat  pitch  roof  with  beams  and  columns  knee 
braced  together,  a  double  pitch  being  given  to  the  center  part  by 
blocking  the  purlins  up  to  the  proper  slope.  Fig.  138  is  anoth'er  sim- 
ple roof  supported  on  two  lines  of  inside  columns,  the  rafter  bases  of 
the  central  part  being  tied  together  with  rods.  Figs.  147  and  148 
have  lean-to  trusses  with  steep  rafter  pitches  under  the  skylights 
near  the  walls,  the  pitch  decreasing  towards  the  center,  leaving  a 
greater  side  window  area  without  unnecessarily  increasing  the 
height  of  the  building.  Fig.  151  receives  roof  light  entirely  through 
skylights,  and  is  the  form  used  for  the  Coventry  Ordnance  Works, 
which  are  200  feet  wide  and  980  feet  long.  Figs.  152  to  155  all 
have  inside  gutters  and  drainage,  and  lack  the  stiffness  of  frames 
with  single  pitch  lean-to  trusses.  Figs.  156  to  161  are  building 
frames  with  curved  trusses,  suitable  for  exhibition  halls,  markets 
or  armories.  They  have  a  much  better  and  lighter  appearance  than 
heavy  trusses  with  horizontal  chords,  but  are  not  generally  suitable 
for  shops,  which  need  horizontal  supports  for  shafting,  trolleys  and 
hoisting  appliances. 

TRUSSES. 

Curved  sheets  of  corrugated  iron  without  regular  truss  frames, 
may  be  used  for  spans  up  to  30  feet.  The  sheets  are  riveted  together 
at  the  ends  and  framed  into  an  arch,  the  ends  of  which  thrust 
against  side  angles  tied  together  with  rods.  Large  5-inch  cor- 
rugations have  a  greater  compression  strength  than  smaller  ones, 
and  are  therefore  preferable,  and  the  arch  may  be  braced  with  occa- 
sional struts.  Curved  forms  are  also  largely  used,  especially  in 


STEEL  FRAMING 


121 


Fig.   122. 


Fig.   123. 


Fig.   124. 


Fig.    32.1. 


Fig.   128. 


Fig.   129. 


Fig.   131. 


Fig.  132. 


Fig.  133. 


122 


MILL  BUILDINGS 


Fig.  134. 


Fig.   135. 


Fig.   136. 


Fig.   137. 


Fig.   138. 


Fig.  139. 


Fig.   140. 


Fig.   141. 


Fig.  142. 


Fig.   143. 


Fig.   144. 


Fig.   145. 


STEEL  FRAMING 


Fig.   146. 


Fig.   148. 


^(rts     ^\7^>^ 


Fig.  150. 


Fig.   152. 


Fig.   154. 


Fig.   156. 


123 


Fig.   147. 
^3/\/     \fo>^ 


Fig.   149. 


Fig.   151. 


Fig.   153. 


Fig.   155. 


Fig.   157. 


124 


MILL  BUILDINGS 


r^ 


Fig.  158. 


Fig.   159. 


Fig.  160. 


Fig.  161. 


Fig.   162. 


Fig.   163. 


Fig.  164. 


Fig.   165. 


Fig.   166. 


Fig.  167. 


Fig.   168. 


Fig.  170. 


Fig.  171. 


Fig.  172. 


Fig.  173. 


Fig.   174. 


Fig.  175. 


Fig.   176. 


Fig.   177. 


Fig.   178. 


F*g.   179. 


Fig.  180. 


STEEL  FRAMING  125 


Fig.  181.  Fig.  182. 


Fig.    183.  Fig.   184. 

Europe,  for  monitors  and  ventilators,  and  are  believed  to  present  a 
better  appearance. 

Standard  types  of  steel  roof  trusses  and  building  frames  are 
shown  in  Figs.  122  to  184.  Figs.  162  to  171  are  Fink  trusses  suit- 
able for  spans  as  indicated,  the  last  one  having  vertical  rafter 
braces.  Fink  trusses  are  more  commonly  used  than  any  other  kind, 
and  are  economical  because  the  struts  are  short,  and  the  longer 
web  members  are  in  tension.  Figs.  172  and  173  are  forms  of  Eng- 
lish roof  trusses  with  vertical  members,  which  in  Fig.  172  are  in 
compression, and  in  Fig.  173  in  tension.  By  comparing  Figs.  171, 
172,  and  173,  the  economy  of  the  Fink  truss  will  be  seen,  for  the 
longest  compression  members  in  the  English  truss  are  avoided. 
Figs.  163  and  171  are  similar,  except  that  the  latter  has  struts  in 
a  vertical  position,  instead  of  normal  to  the  rafter.  Vertical  truss 
members  are  often  necessary,  as,  for  example,  in  hip  trusses,  for  the 
attachment  of  intermediate  trusses  and  rafters.  They  are  also  pref- 
erable for  small  roof  pitches,  as  the  truss  members  can  be  arranged 
with  more  effective  angles  of  intersection.  Trusses  with  small  rafter 
pitch  are  most  conveniently  framed  with  vertical  and  diagonal 
members  (Figs.  124  and  178),  rather  than  with  rafter  braces  nor- 
mal to  the  upper  chords  (Fig.  174).  When  trusses  are  not  pro- 
portioned for  concentrated  loads  at  any  point  of  the  bottom  chord, 
vertical  braces  are  then  needed  only  for  supporting  the  top  chord 
(Fig.  182),  and  the  additional  pieces  of  Fig.  179,  with  the  corre- 
sponding connection  plates  and  details,  are  saved. 

Side  or  lean-to  trusses  with  a  slope  in  one  direction  only  are 
illustrated  in  the  various  building  frames.  It  is  economy  of  column 
sections  to  apply  the  load  from  side  truss  as  low  down  on  the 
column  as  possible.  The  form  of  Fig.  142  is,  therefore,  preferable 
to  1,41,  and  is  the  one  generally  used. 

All  parts  of  roof  trusses,  including  members  in  tension,  should 
be  made  stiff,  for  flat  bars  are  liable  to  be  bent  in  shipping,  and 
when  once  bent  are  rarely,  if  ever,  straightened.  The  center  line 
of  members  should  meet  at  panel  points  when  stresses  are  large, 


126 


MILL  BUILDINGS 


even  though  the  connection  plates  must  be  increased  (Fig.  185),  but 
when  stresses  are  small  it  is  better  to  arrange  the  truss  members  at 
the  panel  points  to  produce  the  smallest  plate  and  the  fewest  num- 
ber of  rivets  (Fig.  186).  A  common  truss  connection  shown  in 
Fig.  187  is  faulty  in  having  secondary  or  eccentric  stress  due  to 
the  center  line  of  web  members  meeting  outside  the  chord,  but  it 
makes  a  neater  detail  and  is  satisfactory  for  light  members.  Of 


-» -Q  -Q -0-  e -» -G - G  -G  -O-  -Or- - 

Fig.  185. 


Fig.  186. 


Fig.  181 


the  three  details  for  truss  connections  to  columns  (Figs.  188,  189, 
190),  the  eccentric  stress  in  the  first  one  is  avoided  in  the  latter 
two,  which  are,  therefore,  preferable  for  heavy  members. 

Fire  curtains  in  the  roof  at  intervals  of  one  or  two  hundred 
feet,  are  recommended  by  insurance  companies,  to  prevent  fire  from 
spreading  under  the  roof,  and  these  consist  of  thin  solid  web  plates 
instead  of  separate  members  in  occasional  trusses. 


E,-f-.-:— ^ 
IK 


Fig.   188. 


Fig.  189. 


Trusses  must  be  sti-ff  enough  to  permit  handling  without  injury, 
and  small  ones  completely  riveted  in  the  shop  should  have  bent 
cover  plates  at  the  peak.  Without  such  a  cover,  small  trusses  loaded 
on  a  wagon  for  delivery,  would  bend  at  the  center  (Fig.  191). 

Single-truss  systems,  or  those  composed  of  a  series  of  united 
triangles,  are  preferable  to  trusses  with  double  systems  of  web 
members  crossing  at  the  center,  for  in  the  latter  case  the  amount 
of  stress  borne  by  each  system  is  indeterminate. 

The  number  and  length  of  rafter  panels  depend  on  the  method 
of  loading  the  trusses.  When  purlins  are  used,  the  rafter  braces 
should  preferably  come  under  the  purlin,  and  rafters  with  combined 


STEEL  FEAMING 


127 


direct  compression  and  cross  bending  require  more  trussing  than 
those  for  compression  only.  The  length  of  truss  panels  depends 
also  on  the  depth  of  truss.  Shallow  trusses  should  have  shorter 
panels  than  deeper  ones,  to  make  the  diagonal  braces  lie  more  nearly 
at  an  angle  of  45  degrees  with  the  horizontal.  Trusses  which  have 
•a  small  end  depth  may  have  shorter  web  panels  towards  the  end 
than  near  the  center.  In  the  design  of  trusses,  as  well  as  other 
parts,  the  essential  requirements  must  first  be  met,  and  the  design 
developed  according  to  those  requirements.  To  arbitrarily  select  a 


Fig.   190. 


Fig.   191. 


system  of  framing  without  studying  the  needs  of  the  case  is  almost 
sure  to  result  in  waste. 

The  rafters,  bottom  chords  and  main  struts  should  be  made  sym- 
metrical, as  of  double  angles,  but  single  angles  may  be  used  for 
minor  braces.  The  proper  form  of  truss  is  often  fixed  by  external 
requirements.  The  width  of  monitor  may  make  Fig.  175  prefer- 
able to  Fig.  169,  and  a  flat  ceiling  will  require  a  straight  bottom 
chord. 

Figs.  192  and  193  show  the  right,and  wrong  way  of  outlining  a 


Fig.   192. 


Fig.   193. 


steep  pitch  roof  with  monitor,  while  Figs.  194  and  195  show  right 
and  wrong  ways  of  outlining  trusses  with  a  flat  rafter  pitch.  In 
the  latter  case,  it  is%  economical  to  use  the  shortest  web  members  in 
compression  and  the  longer  or  diagonal  ones  in  tension. 

When  a  floor  or  other  heavy  load  is  suspended  from  the  trusses 
(Fig.  197),  the  principal  details  will  be  at  the  eaves,  peak  and  the 
two  suspension  points. 


128 


MILL  BUILDINGS 


The  end  connection  plates  on  long,  shallow  trusses  may  be  so 
large  as  to  make  a  solid  web  preferable  in  the  end  panel,  but  these 
plates  may  be  lightened  by  cutting  holes  in  them.  When  holes  are 
located  as  shown  in  Fig.  196,  web  stress  is  possible  in  one  diagonal 
direction  only. 


Fig.    194. 


Fig.   195. 


TEUSS  CONNECTIONS. 

The  choice  between  pins  or  rivets  for  roof  connections  depends 
largely  upon  the  relative  cost  of  manufacture  and  erection.  Bolts 
or  rivets  are  generally  cheaper  than  pins  for  all  ordinary  spans  and 
conditions,  but  pins  may  be  preferable  for  long  spans  and  difficult 
erection,  as  illustrated  by  several  large  train  shed  roofs. 


Floor  Load  =  350  Ibs.  per  sq.  it.  Floorjjnt g'Crown 


Fig.   196. 


TEUSS  DEPTH. 

The  economical  depth  of  truss  is  usually  from  one-fifth  to  one- 
seventh  of  the  span,  but  special  conditions  may  require  a  less  depth, 
and  the  weight  is  not  seriously  affected  by  a  small  variation.  Deeper 
trusses  have  lighter  chords  but  longer  web  members,  while  shallow 
trusses  have  heavier  chords  and  shorter  web  members,  and  these  two 


STEEL  FRAMING 


129 


variations  tend  to  balance  each  other.     Extra  depth  for  flat  pitch 
trusses  may  be  secured  as  shown  in  Figs.  20.,  179  or  198. 

RAFTERS. 

The  most  convenient  form  of  rafter  for  riveted  trusses  is  made 
of  two  angles  placed  back  to  back  with  connection  plates  between 
them  at  the  joints  (Fig.  199).  The  angles  should  be  riveted  to- 
gether at  intervals  of  2  to  4  feet,  so  that  the  strength  of  each  angle 


Ridqe  Strut 


Fig.  197 


in  compression  will  be  at  least  equal  to  the  strength  of  the  two  com- 
bined for  its  greatest  unsupported  length.  If  the  rafter  is  subjected 
to  bending  from  directly  applied  loads,  a  continuous  plate  between 
the  angles  is  then  economical  (Figs.  197,  219),  or  larger  angles  and 
shorter  panels  may  be  used  instead;  or,  when  bending  stress  is 
excessive,  the  rafter  may  be  made  of  four  angles  and  a  web  plate 
(Fig.  198).  The  kind  of  roof  covering,  thickness  of  plank  or  slab, 
and  spacing  of  purlins,  must  be  fixed  before  the  rafter  can  be 
designed.  If  it  carries  directly  a  part  of  the  roof  load,  as  when 


130 


MILL  BUILDINGS 


plank  is  fastened  to  nailing  pieces  on  the  rafter,  it  must  then  be 
proportioned  for  bending.  The  rafter  bracing  in  Fink  trusses 
should,  wherever  possible,  be  at  the  load  points. 

BOTTOM  CHORDS. 

The  bottom  chords  of  roof  trusses  for  all  ordinary  cases  are 
most  conveniently  made  like  the  rafters,  of  two  angles  placed  back 
to  back,  but  if  weight  must  be  borne  at  any  point,  a  continuous  plate 
should  be  inserted  between  the  angles,  or  two  channels  used.  A 
stiff  chord  may  also  be  made  of  four  angles  laced  together  (Fig. 
108).  It  is  often  necessary  to  have  the  chord  strong  and  stiff 
enough  so  that  a  hoisting  block  can  be  attached  to  it  at  any  point, 
or  a  trolley  operated  on  the  lower  flange.  This  or  other  require- 
ments may  necessitate  a  horizontal  member.  The  appearance  of 


I     ^t-Pimi-VSW 

o'a' >|*. .7 

Half     Elevation   of  Prei9 


Fig.  198. 


a  truss  is,  however,  improved  by  a  slight  camber  not  exceeding  one  to 
two  feet,  but  a  greater  rise  is  wasteful  of  section  and  may  necessitate 
bending  the  bracing  plates. 

When  the  vertical  mast  of  a  jib  crane  is  supported  at  the  top  by 
struts  between  the  trusses,  the  lower  chords  must  be  proportioned 
as  compression  members  for  the  bracing  system,  in  addition  to 
resisting  the  combined  tension  from  crane  stress  and  roof  loads. 


STEEL  FEAMING 


131 


When  trusses  are  spaced  not  more  than  8  to  10  feet  apart,  the 
lower  chords  form  a  convenient  support  for  shafting,  although  many 
shops  are  now  placing  shafting  in  a  basement  or  tunnels  beneath  the 
floor. 

TRUSS  SPACING. 

The  weight  of  purlins  is  a  minimum  when  trusses  are  placed 
close  together,  but  since  the  weight  of  trusses  is  proportional  to 
the  load  upon  them,  the  least  total  weight  of  truss  and  purlin  com- 
bined would  result  from  close  truss  spacing.  This  is  true  only  when 
the  small  sections  required  for  light  trusses  can  be  realized,  which  is 
usually  impossible.  Comparative  estimates  show  that  the  most  eco- 
nomical truss  spacing  is  one-fourth  to  one-eighth  the  span,  or  10 
to  15  feet  for  spans  up  to  50  feet,  and  15  to  20  feet  for 
spans  of  50  to  100  feet.  Above  100  feet,  the  economical 
truss  spacing  is  proportionately  increased.  When  plank 
is  laid  directly  on  the  rafters,  truss  spacing  should  not 
exceed  8  feet  for  2-inch  plank  and  10  feet  for  3-inch  Fig.  199. 
plank.  For  economy  of  framing,  the  spacing  should  be 
large  enough  to  stress  the  smallest  members  up  to  their  safe  working 
load. 


T 


Fig.  200. 


132  MILL  BUILDINGS 

WEIGHT  OF  TRUSSES. 

Curves*  giving  the  weight  of  trusses  for  spans  and  loads  of  any 
amount  are  shown  in  Fig.  119.     The  total  weight  of  steel  is 

LS2 

W  = 

C 

when  W  =  total  weight  of  truss  in  pounds, 

L  =  the  total  truss  load  per  lin.  ft.  of  span, 

S  =  span  in  feet,  and 

C  =  a  constant  varying  from  3,000  to  3,700,  generally  taken  at  1,200. 


Fig.  201. 

The  truss  weight  is  therefore  more  affected  by  the  length  of  span 
than  by  any  other  factor. 

MONITOR    FRAMES. 

Some  forms  of  monitor  frames  are  shown  in  Figs.  202  to  210, 
and  they  are  further  illustrated  in  connection  with  roof  trusses  and 
building  frames.  Only  enough  members  are  needed  to  support  the 
covering  and  hold  the  frame  in  position  without  distortion.  Fig. 
202  is  the  kind  generally  used  for  narrow  monitors  not  over  8  or 
10  feet  wide,  while  Fig.  203  is  suitable  for  monitor  with  sloping 
glass  sides,  to  better  throw  the  light  to  the  floor.  The  monitor  rafter 
of  Fig.  207  has  a  greater  roof  slope  than  the  truss  on  which  it 
stands,  and  is  used  when  the  monitor  roof  has  a  skylight  covering. 
The  two-story  monitor  (Fig.  208)  has  side  windows  on  the  lower 

*  H.  G.  Tyrrell  in  London  Engineering,  July  25,  1902. 


STEEL  FRAMING 


133 


rise  and  ventilator  shutters  on  the  upper  one.  Fig.  209  is  suitable 
for  ventilating  only  with  shutters  or  louvres  on  the  side. 

Monitors  are  often  made  as  shown  in  Figs.  175  or  206,  when  a 
clear  space  is  needed  for  coal  conveyors,  or  for  men  in  cleaning 
windows  or  skylights. 

Electric  light  stations  often  admit  wires  to  the  building  through 
the  monitors,  and  wire  supports  with  insulation  are  then  needed  on 
the  sides.  One  or  more  panels  of  the  regular  monitor  can  be  used 
for  this  purpose  if  required. 


Fig.  202. 


Fig.   203. 


Fig.   204. 


Fig.   205. 


Fig.   206. 


Fig.   207. 


Fig.  208.  Fig.  209. 


GIRTHS    AND   PURLINS. 


Fig.   210. 


Wall  girths  and  roof  purlins  are  both  used  to  support  the  cover- 
ing, and  their  details  and  connections  are  similar,  but  roof  purlins 
must  be  capable  of  sustaining  the  greatest  load.  It  is  economical, 
for  single  roofing  slabs  or  sheets,  to  span  the  opening  between  at 
least  three  purlins,  for  the  covering  then  has  the  added  strength  of 
continuity.  The  proper  purlin  spacing  for  corrugated  iron  and 
slate  is  given  in  Part  IV,  and  the  spacing  for  other  material  must 
be  proportioned  to  its  strength  or  thickness.  Two-inch  plank  must 
be  supported  at  intervals  of  8  feet,  and  3-inch  plank  at  not  more 
than  10  feet.  A  line  of  purlins  should  be  placed  under  the  end  of 
the  corrugated  iron  at  the  eave,  to  prevent  its  being  bent  or  injured, 
but  the  projection  need  not  exceed  12  to  15  inches.  When  a  better 


134 


MILL  BUILDINGS 


appearance  is  desired,,  a  molded  sheet  metal  cornice  may  be  added 
(Fig.  461). 

Steel  purlins  are  made  of  simple  shapes,  either  with  or  without 
trussing.  Angles,  channels,  beams  and  zee  bars  are  commonly  used, 
the  first  being  most  easily  cut,  and  usually  the  cheapest.  Simple 
angles,  untrussed,  can  be  used  for  spans  up  to  15  feet,  and  trussed 
angles  or  other  shapes  up  to  20  feet.  Angle  purlins  on  roofs  should 
be  placed  as  shown  in  the  upper  view  of  Fig.  211,  rather  than  as  in 

the  lower,  for  in  the  first  position 
they  have  a  greater  vertical  resist- 
ance to  bending.     It  is  economical 
to  use  simple  shapes  such  as  beams 
or   channels,   even   with   a   slightly 
greater  weight,  than  to  incur  the  ex- 
tra  shop  expense  of  trussing.  Angles 
are  trussed  with  light  bent  rods  and 
struts    (Fig.    213),    or   with   other 
light    angles    with    riveted    joints,, 
bent  rods  being  the  cheaper.     Pur- 
lins should  have  a  line  of  ^-inch  rods  in  the  center  of  each  panel, 
to  prevent  their  sagging  vertically  in  the  wall,  or  down  the  plane 
of  roof,  when  panel  lengths  exceed  15  feet. 

Simple  shapes  are  preferable  to  trussed  purlins,  not  only  for 
their  less  shop  cost,  but  also  for  their  better  appearance,  as 


Fig.   211. 


Fig.   212. 

1 

H 
i 

«_  .    a'o"  ->U  4'o"    — 
1    ' 

fii 

c 

L££s&22i*f'z 

If 

i  » 

Fig.  213. 


STEEL  FRAMING 


135 


too  much  trussing  and  bracing  obstruct  the  roof  light  and  produce 
complexity. 

Angles,  channels  and  zee  bars  are  bolted  to  the  rafters  through 
angle  clips  (Fig.  214),  but  beams  must  be  fastened  directly  through 
the  flanges.  Clips  and  pur- 
lins are  fastened  with  bolts 
instead  of  rivets,  for  the 
joints  have  little  stress,  and 
bolted  joints  are  cheapest. 
Purlins  are  fastened  to 
brick  gable  walls,  either  by 
bolting  to  an  angle  anchored 
in  brickwork  (Fig.  215),  or  with  rod  anchors  hooked  through  the 
purlins  and  driven  into  the  brick  joints  (Fig.  216).  Openings 
around  stacks  or  skylights  should  be  framed  with  pieces  standing 
out  an  inch  or  two  for  clearance,  with  diagonal  corner  pieces  if 
necessary.  They  may  be  surrounded  with  a  bent  angle  and  the 
whole  made  watertight  with  a  flashing  hood  (Fig.  483).  When 
the  roof  is  fastened  with  nails,  wood  spiking  pieces  must  be  bolted 
to  the  top  or  sides  of  purlins,  and  these  are  always  needed  for 
translucent  fabric  skylight,  unless  wood  purlins  are  preferred. 


Fig.  214. 


Fig.  215. 


Fig.  216. 


The  application  of  steel  wall  girths  is  shown  in  the  market 
building  design  (Fig.  30),. and  the  proper  spacing  is  given  in 
Table  XLVII. 

JACK  RAFTERS. 

Jack  rafters  are  not  very  generally  used  on  mill  buildings,  except- 
ing to  support  slate  purlins,  for  trusses  are  not  often  placed  more 
than  20  feet  apart.  In  panel  lengths  exceeding  20  feet,  it  is  eco- 
nomical to  use  a  few  lines  of  heavy  purlins,  supporting  one  or  two 
intermediate  rafters,  which  carry  the  small  purlins  on  which  the 
roofing  rests.  This  construction  is  generally  used  on  large  buildings 
such  as  train  sheds  or  exhibition  halls,  for  wider  truss  spacing.  For 


136 


MILL  BUILDINGS 


non-fireproof  buildings,  wood  rafters  may  -be  placed  16  to  24  inches 
apart. 

CKANE  SUPPORTS. 

Building  frames  for  shops  with  heavy  cranes  might  more  fit- 
tingly be  called  covered  crane  ways  than  shop  buildings,  for  most 
of  the  framing  material  is  in  the  crane  supports.  Modern  locomo- 
tive shops  have  traveling  cranes  of  120  tons'  capacity  or  greater 
(Fig.  217),  strong  enough  to  lift  an  entire  engine  and  transfer 


it  to  another  place.  It  was  formerly  the  practice  to  design  manu- 
facturing plants  with  very  limited  crane  capacity,  but  more  recent 
shops  have  large  cranes  for  occasional  use  and  smaller  ones  for 
lighter  loads  and  regular  service.  Carefully  arranged  crane  framing 
is  important  because  the  cranes  will  have  frequent  or  constant  use, 
while  wind  or  snow  loads  may  seldom  or  never  be  realized. 

Shop  lifting  and  handling  appliances  are  made  in  great  variety, 
including  tramrails,  hoists  and  trolleys,  traveling  bridge  cranes,  sta- 
tionary and  traveling  jib  cranes,  etc. 

Trolleys  run  either  on  the  bottom  flange  of  beams,  as  in  the 
shops  (Figs.  21  and  23).  or  on  the  bottom  chords  or  tie  beams  of 
trusses,  and  the  hoists  attached  to  them  are  operated  by  compressed 
air,  electricity  or  hand  chains. 

Traveling  bridge  cranes  are  supported  on  girders  between  adjoin- 
ing lines  of  columns,  and  are  often  made  of  different  capacities,  in 
two  or  more  tiers,  one  above  the  other.  The  large  cranes  would,  of 
course,  lift  the  smaller  loads,  but  as  they  are  heavy  and  slower  to 
operate,  it  is  a  saving  of  time  to  install  smaller  cranes  for  ordinary 
light  service  (Fig.  218) .  The  crane  girders  and  supporting  columns 


STEEL  FEAM1NG 


137 


should  be  rigidly  connected 'to  the  roof  trusses,  for  if  standing  alone 
or  merely  fastened  to  the  walls.,  a  slight  variation  between  the  cen- 
ters of  crane  rails  may  occur,  causing  the  crane  to  bind  or  run 
untrue.  It  is  good  practice  to  fasten  rails  to  their  bearings  in  such 


10  Ton  Crane 


\     (  2-Ton  Travel 
\\    ^  Jib  Cranes 


r  -x— xxj«^ 


Fig.  218. 

a  way  as  to  admit  of  slight  horizontal  adjustment  (Fig.  221),  so 
the  crane  can  always  be  made  to  run  true  and  even.  Provision  is 
sometimes  made  on  side  wall  columns  for  supporting  traveling  yard 
cranes,  by  extending  columns  above  the  roof,  or  framing  girders 
into  them  (Fig.  222).  Fig.  219  shows  a  system  of  framing  for 
traveling  bridge  cranes  over  the  center  aisle  of  an  iron  works  shop, 
with  two  sets  of  cranes,  one  above  the  other.  The  lower  crane  spans 
the  entire  center  floor  space  between  the  columns,  while  the  upper 
ones  are  only  half  as  long,  and  are  supported  at  the  center  of  the 
span  on  suspension  brackets  from  the  trusses. 

Tables  with  outside  dimensions  and  required  clearances  for 
electric  traveling  cranes  are  given  in  Chapter  III. 

Traveling  jib  cranes  (Fig.  223)  supported  from  the  walls  or 
inside  line  of  columns  are  convenient  and  much  used  in  modern 


138 


MILL  BUILDINGS 


Mom  Column. 


Fig.  219. 


STEEL  FEAMING 


139 


shops.  They  are  light,  can  be  easily  and  quickly  handled,  and  are 
used  in  single  lines  (Fig.  224)  or  in  double  tiers,  one  above  another 
(Fig.  225).  The  framing  to  support  some  makes  of  traveling  jib 
cranes  is  shown  in  Figs.  226,  227  and  228. 


Stresses  tnarked  are  Mais  from  unloaded  IO~Ton  Cranes, 
loaded  25-  Ton  Cranes,  and  from  Imporcf 


Fig.  220. 

The  older  form  of  stationary  jib  crane,  standing  on  the  ground, 
has  the  upper  end  of  the  mast  supported  by  a  system  of  framing 
connected  to  the  truss  chords.  These  cranes  produce  heavy  stresses 
in  the  bottom  chord  bracing,  which  must  be  properly  transferred  to 
the  walls  or  columns,  and  thence  to  the  foundations. 

Crane  girders  may  have  either  a  single  or  a 
double  web,  the  latter  (Figs.  200,  229)  with  its 
wide  cover  plate  producing  a  stiffer  frame.  Side 
longitudinal  trusses  to  support  intermediate  roof 
trusses,  should  be  either  disconnected  entirely 
from  the  crane  system  or  fastened  with  slotted 
joints,  so  movements  of  the  traveling  cranes, 
and  deflections  or  vibrations  of  the  crane  beams, 
will  not  be  transmitted  to  the  side  wall  or  roof 
system,  and  break  the  window  glass  or  skylight. 


Fig.  221. 


140 


MILL  BUILDINGS 


STEEL  FRAMING 


141 


Fig.  223. 


Fig.  224. 


Fig.  225. 


142 


MILL  BUILDINGS 
COLUMNS. 


The  weight  of  steel  in  trusses  and  girders  is  affected  more  by  the 
number  and  frequency  of  columns  than  by  any  other  factor.  Fram- 
ing with  wide  column  spacing  has  a  greater  weight  and  cost,  than 
similar  framing  with  columns  closer  together.  In  many  lines  of 
manufacturing,  the  presence  of  columns  is  a  disadvantage,  for  they 
interfere  with  handling  the  large  material  and  products,  but  in 
shops  for  the  manufacture  of  small  goods,  columns  may  be  of  benefit 
for  supporting  shafting  or  dividing  the  floor  into  separate  parts. 


Side  Efevation 
Track   Girder   for  Overhead  Crane 


Flange  Stress  6O.OOO)  for  2  Crane 
End  Shear  4-3.000 


Upper  Part  of  Column 


^ear  35.OOO  J  . 
Track  Girder   for   5- Tor,  Wall  Crane 

Fig.   226. 


In  order  to  have  few  inside  columns,  part  of  the  regular  roof  trusses 
are  sometimes  carried  on  longitudinal  trusses,  which  serve  also  as 
effective  column  bracing.  Fig.  229  has  regular  transverse  trusses 
20  feet  apart,  with  alternate  ones  on  lattice  girders,  making  a  clear 
space  of  40  feet  between  the  principal  inside  columns,  while  Fig. 
220  has  trusses  12  feet  apart,  with  every  third  one  supported  directly 
on  columns  36  feet  apart. 

The  trusses  and  other  parts  should  be  so  arranged  that  loads  are 
delivered  to  the  columns  as  low  down  as  possible,  for  long  loaded 
columns  require  greater  section  than  shorter  ones.  Diagonal  com- 
pression members  in  connecting  trusses  (Fig.  142)  are  therefore 


STEEL  FEAMING 


143 


fof  Transverse  Truss. 


often  preferable  to  tension  members  (Fig.  141),  for  while  the  truss 
members  are  increased,  the  extra  expense  is  more  than  offset  by  the 
saving  in  and  greater  security  of  the  columns,  which  may  be  sub- 
ject to  jars  or  impact. 

Fig.  230  shows  a  variety  of  common  column  forms,  the  ones 
most  used  being  a,  b  and  c.  Closed  sections  should  not  be  used,  for 
connections  to  them  are  not  easily  made,  and  their  inside  condition 
cannot  be  inspected.  Eolled  H  shapes  (Fig.  230d)  with  wide 
flanges,  which  have  long  been  used  in  Europe,  are  now  made  in 
America,  and  are  well  suit- 
ed for  shop  columns,  sav- 
ing much  riveting;  but 
they  are  sold  at  a  higher 
price  per  pound  than  plate 
and  angles,  and  this  tends 
to  offset  the  saving  in  shop 
work.  A  column  which  is 
quite  economical,  though 
inconvenient  for  connec- 
tions, consists  of  round 
wrought  steel  pipe  filled 
with  concrete,  the  12-inch 
size  being  strong  enough 
to  support  100  tons  or 
more.  Round  cast  iron  col- 
umns are  frequently  used 
for  supporting  gallery  or 
upper  floors,  but  on  ac- 
count of  its  brittle  nature, 
cast  iron  is  not  recom- 
mended for  structural  use. 

Open  sections  made  of 
plates  and  angles  are  con- 
venient for  building  into 
walls,  as  their  width  can  be 
made  to  suit  any  size  of  brick,  and  they  are  easily  enclosed. 
When  the  columns  extend  through  the  wall  without  being  en- 
closed with  pilasters,  web  lattice  is  unsuitable,  as  the  space 
between  the  angle  bars  of  the  column  leaves  an  opening  through 
the  wall,  and  a  solid  web  plate  should  be  used  instead.  Enclosed 
wall  columns  may  have  provision  for  expansion  by  leaving 


Floor  Line 
Fig.   227. 


144 


MILL  BUILDINGS 


20'I-80# 
frSMiSpl.pf'S, 

&%£'Spl  PI'S. 
>t5"f-4Z* 


Fig.   228. 


STEEL  FEAMING 


145 


146  MILL  BUILDINGS 

clearance  between  the  brick  and  steel  (Fig.  231),  the  brick  casing 
being  a  complete  enclosure  without  touching  any  part  of  the  column. 
Wall  columns  having  excessive  bending  stress  from  knee  braces 
should,  when  necessary,  be  reinforced  on  the  inner  or  greatest  com- 
pression flange  with  extra  section,  as  shown  in  Fig  232. 

Pier  shed  columns  are  sometimes  sloped  (Fig.  198)  or  extended 
above  the  roof  (Fig.  196)  to  support  lattice  girders  or  framing, 
which  are  useful  in  unloading  goods  from  vessels. 

I  H  II  I 

abed 

i  H  n  i 

e  f  g  h 

Fig.  230. 

When  provision  is  made  for  extending  the  building,  the  principal 
end  columns  should  be  similar  to  the  regular  ones,  for  they  can  then 
be  used  for  the  extension,  without  strengthening  or  replacing  them, 
and  much  expensive  alteration  will  be  avoided.  Regular  roof  trusses 
should  also  be  used,  and  the  end  enclosed  with  a  temporary  frame 
of  columns  and  girths  covered  with  board,  or  corrugated  iron 


a  b 

TT 


Fig.  231.  Fig.  232. 

sheathing.  End  columns  should  have  a  full  symmetrical  section 
up  to  the  level  of  the  bottom  chords,  above  which  the  outer  two 
angles  only  may  be  extended  to  the  roof,  forming  a  convenient  sup- 
port for  the  gable  purlins.  The  end  of  buildings  without  provision 
for  extension  should  have  columns  10  to  15  feet  apart,  supporting 
a  gable  rafter  instead  of  an  end  truss,  with  a  stiff  member  at  the 
bottom  chord  level  to  act  as  chord  for  the  horizontal  bracing  s}^stem. 
This  construction  is  much  cheaper  than  using  end  trusses,  but  is 


STEEL  FRAMING 


147 


not  convenient  for  extending  the  building.  End  crane  girder  col- 
umns must  be  made  of  proper  strength  to  carry  the  crane  loads,  and 
must  also  have  end  girth  connections. 

It  is  sometimes  convenient  to  frame  the  end  of  a  building  so 
the  traveling  shop  crane  with  its  load  can  be  run  out  into  the  loading 
yard  (Fig.  621).  An  arrangement  of  this  kind  was  used  by  the 
author,  in  1898,  in  the  design  and  construction  of  a  structural  shop 


Fig.  233. 


Fig.  234. 

in  the  East,  and  was  found  satisfactory.  The  end  is  enclosed  with 
rolling  steel  shutters,  held  in  place  by  hinged  posts,  which  are  swung 
up  out  of  the  way  when  the  end  is  opened  for  the  crane.  The  end 
may  be  partly  enclosed  with  brick,  as  shown,  with  only  the  center 
panel  fully  open,  or  each  of  the  three  panels  may  have  rolling  shut- 
ters to  the  floor.  A  car  barn  with  the  end  similarly  enclosed  with 
rolling  shutters  is  shown  in  Fig.  622. 

Crane  columns  must  have  proper  seats  to  support  the  crane 
girder.  Brackets  are  suitable  only  for  light  cranes,  as  they  produce 
eccentric  column  loads,  which  are  a  frequent  cause  of  excessive 
vibration  in  improperly  designed  buildings,  resulting  continually 


148  MILL  BUILDINGS 

in  broken  skylights  and  windows.  A  properly  designed  column  for 
supporting  crane  girders  will  be  as  outlined  in  Fig.  235a,  and  not 
like  b  or  c,  as  both  the  latter  have  eccentric  loading.  Columns  sup- 
porting two  tiers  of  crane  girders,  one  above  the  other.,  may  have 
girders  for  the  lighter  crane,  supported  as  illustrated  in  Fig.  219, 
but  crane  columns  must  in  all  cases  be  fastened  to  the  roof  trusses 
or  otherwise  tied  together  at  the  top,  to  prevent  the  crane  track  from 
getting  out  of  line.  If  bracket  or  eccentric  connection  is  necessary 
for  either  the  roof  or  crane  loads,  it  should  be  used  for  the  smaller 
of  the  two,  which  is  frequently  the  roof  load 
on  ^e  c|ear  sfory  column.  This  construction 
is  illustrated  in  Figs.  228  and  218.  Struts 
L,  L  L  should  connect  the  upper  end  of  clear  story 
wall  and  wall  columns  at  the  eave. 

Traveling  jib  cranes  necessitate  quite  elabo- 
rate framing  on  the  columns  to  carry  the  lines 
of  rails  for  their  support  (Figs.  226,  227,  228), 
and    longitudinal    trusses    require    additional 
framing.     In  detailing  columns,  the  connections  should  first  be 
designed,  and  minor  details  such  as  lattice  or  batten  plates  located 
afterwards. 

The  large  flaring  bases  of  interior  columns  (Figs.  219,  220) 
should  be  depressed  below  the  floor  to  avoid  obstruction  and  should 
preferably  be  coated  heavily  with  asphalt  paint.  They  should  have 
only  the  fewest  possible  number  of  rivets  in  the  base  to  avoid  the 
expense  of  countersinking.  An  original  table  for  the  weight  of 
cast  iron  column  bases  similar  to  Fig.  238  is  as  follows:* 

TABLE    XXIV.* 

WEIGHT    OF    CAST    IRON    COLUMN    BASES. 

22X22  ins 600  Ibs.  32X32  ins 1,340  Ibs. 

24X24  ins 750  Ibs.  34X34  ins 1,450  Ibs. 

26X26  ins... 880  Ibs.  36X36  ins 1,600  Ibs. 

28X28  ins 1,020  Ibs.  38X38  ins 1,720  Ibs. 

30X30  ins 1,180  Ibs.  40X40  ins 1,850  Ibs. 

A  circular  column  form  is  sometimes  preferable  to  open  steel 
work,  in  which  case  the  interior  columns  may  be  enclosed  for  a 
height  of  5  feet  above  the  floor  with  concrete,  held  in  place  with  a 
light  sheet  metal  form.  The  sheet  metal,  if  allowed  to  remain, 
makes  a  smooth  resisting  surface,  and  may  be  preserved  by  painting. 


H.  G.  Tyrrell,  in  Architects'  and  Builders'  Magazine,  Jan.  1903. 


STEEL  FRAMING 


149 


Fig.  236. 


Fig.  238. 


150 


MILL  BUILDINGS 


Buildings  may  occasionally  be  more  convenient  when  made 
without  any  interior  columns,  as  in  the  armory  and  drill  hall 
(Figs.  239  to  241). 


Fig.   239. 


Fig.  241. 
See  Architects'  &  Builders'  Magazine,  October,  1901. 


STEEL  FKAMING  151 

FLOOR  FRAMING. 

Steel  floor  framing  may  have  steel  for  all  or  only  part  of  the 
supports.  The  cross  floor  girder  at  the  panels  may  span  the  clear 
space  between  main  columns  (Fig.  222)  or  may  have  one  or  more 
additional  columns  under  it  (Fig.  20),  which  will  greatly  lessen 
the  combined  cost  of  girder  and  columns.  Heavy  floor  girders  are 
shown  in  the  pier  shed  (Fig.  196).  Floor  joist  between  the  girders 
may  be  of  either  steel  or  wood,  and  may  rest  on  top  of  the  girder 
or  frame  into  the  web  (Fig.  410),  the  latter  being  preferable,  as  it 
leaves  greater  head  room  below.  Joists  are  generally  placed  from 
4  to  10  feet  apart,  the  distance  depending  on  the  kind  and  thick- 
ness of  flooring.  They  should  rest  on  angle  seats  on  the  girder 
web  (Fig.  410),  and  steel  beams  are  fastened  with  standard  con- 
nection angles  such  as  are  given  in  any  mill  hand  book.  Plank 
flooring  on  steel  joist  requires  nailing  strips  bolted  or  hooked  to  the 
upper  flange,  to  receive  the  nails.  Cupola  floors  carrying  heavy 
loads  must  be  strongly  framed  and  supported  with  numerous  col- 
umns, and  are  frequently  covered  with  steel  or  cast  iron  floor  plates. 
Gallery  floors  may  be  provided  with  occasional  loading  platforms 
projecting  over  the  main  erecting  floor,  from  which  material  can 
be  lifted  by  the  center  traveling  crane.  A  machine  shop  designed 
by  the  author  has  a  bridge  at  one  end  connecting  the  two  side  gal- 
leries (Fig.  23)  and  two  or  three  lines  of  gas  pipe  fastened  to  the 
columns  with  intermediate  pipe  posts  8  to  10  feet  apart  for  gallery 
railing. 

BRACING. 

The  durability  of  a  mill  building  depends  on  the  efficiency  of  its 
bracing.  Columns,  girders,  trusses  or  other  main  parts  are  rarely 
broken  under  their  loads,  but  building  frames  have  been  racked  to 
pieces  by  continuous  vibration  from  cranes  and  machinery.  Sta- 
tionary and  traveling  cranes,  shafting,  belts,  eccentric  column 
loading,  and  many  other  causes,  tend  to  keep  the  frame  of  a  mill 
building  in  constant  motion,  and  unless  this  is  prevented  by 
thorough  bracing,  it  will  soon  require  expensive  repairs.  When 
the  frame  becomes  loosened,  traveling  cranes  bind  on  their  track, 
production  is  delayed,  and  the  cost  of  operation  is  increased. 
Broken  windows  and  skylights  are  a  common  result  of  insufficient 
bracing,  and  even  when  replaced  they  are  repeatedly  broken  again. 
Lack  of  bracing  affects  operating  expenses,  for  10  to  30  per  cent 
more  power  is  needed  to  run  line  shafting  and  machinery  in  a 
building  that  vibrates  than  in  a  stationary  one.  It  also  causes 
undue  wear  on  machines  and  interferes  with  fine  tool  work. 


152 


MILL  BUILDINGS 


The  general  outline  of  a  building  is  important  in  securing 
rigidity.  A  form  like  Fig.  142  is  more  secure  transversely  than  one 
like  Fig.  155,  and  a  hipped  roof  is  nearly  always  stiff er  than  a  con- 
tinuous pitch.  Angles  braced  together  to  resist  compression  are 
preferable  to  rods,  though  the  latter  have  their  legitimate  use. 
When  rods  are  used,  they  should  have  adjustment  either  by  means 
of  nuts  and  bevel  washers  or  with  clevises  or  turnbuckles.  Standard 
rod  details  are  shown  in  Figs.  242  and  243,  and  light  bracing 
struts  in  Figs.  244,  245  and  246. 


OrderN? 


ftncoyd/rm  Worts 


£lactemith  3/io/t 


Clevises  for . 


Grif, 


Fig.  242. 


OrderN?... 


Pencoytt/ron  Works 
Bridge  anaConslrucUonDe/i* 


Date. 


S/u>rt  Section 


Fig.   243. 


STEEL  FRAMING 


153 


Bracing  must  be  placed  wherever  needed,  the  most  important 
being  that  on  the  rafter  and  bottom  chord,  and  between  columns  in 
the  walls ;  but  other  bracing  may  be  used  in  the  monitor,  and  verti- 
cally between  the  trusses.  Rafters  are  the  chief  compression  mem° 


TT    T 


Fig.  244. 


Fig.  245. 


Fig.   246. 


bers  of  roof  trusses,  and  cross  bracing  must  be  placed  in  occasional 
panels,  corresponding  with  the  bracing  in  the  bottom  chord,  and 
other  rafters  are  tied  to  the  braced  panel  with  the  purlins  and 
roofing.  Eafter  bracing  is  more  needed  during  erection  than  after- 
wards, for  when  applied  and  fastened,  the  roofing  itself  is  the  most 
effective  kind  of  bracing,  especially  when  it  consists  of  plank  or 


X 


X 


Fig.   247. 


Fig.   248. 


concrete.  Car  sheds  or  buildings  without  machinery  are  sufficiently 
rigid  with  occasional  panels  of  the  bottom  chord  braced,  and  two  or 
three  lines  of  longitudinal  spacing  angles  between  the  chords  (Fig. 
247),  but  buildings  with  cranes  require  complete  diagonal  bracing 
systems  (Fig.  248).  The  longitudinal  spacing  struts  of  Fig.  247 


Fig.  249. 


may  be  omitted  in  car  barns  which  have  lines  of  trolley  boards 
fastened  to  the  trusses.  Bottom  chord  bracing,  to  resist  the  action 
of  stationary  and  traveling  jib  cranes,  must  be  carefully  propor- 
tioned to  its  maximum  stresses,  and  these  stresses  must  be  as  care- 


154 


MILL  BUILDINGS 


fully  computed  as  those  in  any  other  truss  system.  It  is  generally 
impracticable  to  transfer  all  the  crane  and  wind  loads  to  the  foun- 
dations at  the  ends  of  the  buildings,  and  knee  braces  from  trusses 
to  columns  are  therefore  introduced.  Wall  bracing  must  be  placed 
in  panels  corresponding  with  those  in  the  rafter  and  bottom  chord, 
and  longitudinal  trusses  (Fig.  220)  make  effective  bracing  between 
interior  columns.  Stiff  bracing  is  nearly  always  more  effective 
than  rods  and  is  therefore  preferable.  Care  should  be  taken  to 
have  the  parts  properly  arranged,  that  chords  and  web  members 
of  any  truss  system  will  act  together,  and  the  joints  should  be  well 
riveted. 

Knee  braces  from  trusses  to  columns  must  join  the  trusses  at 
braced  panel  points,  which  are  capable  of  transmitting  stress  directly 
to  the  truss  frame.  These  braces  should  be  as  deep  as  head  room  or 
clearance  will  permit,  and  they  must  be  capable  of  resisting  both 
tension  and  compression.  Clearance  for  traveling  cranes  frequently 
limits  the  space  available  for  corner  bracing,  and  when  space  above 


Roof  Covering 
Corrlron  No.22 


I-  4*  5  Window  in 
each  Bay -fe'to  swing 

rifchdhrft 


the  center  part  of  the  crane  is  not  required  for  machinery  or  trol- 
leys, it  may  be  preferable  to  give  the  truss  enough  end  depth  so  the 
end  bottom  panels,  which  act  as  knee  braces,  will  be  in  line  or  nearly 
in  line  with  the  bottom  chord  (Fig.  179).  Knee  braces  may  also 
be  placed  between  crane  girders  and  columns,  or  wherever  their 
presence  adds  stiffness  to  the  building. 

After  the  framing  has  been  arranged  and  designed,  it  is  well  to 
review  the  methods  of  bracing  and  see  where  this  feature  of  the 
building  can  be  improved.  Places  ma}''  be  found  where  additional 
bracing  is  needed,  and  other  places  where  it  is  ineffective  or  unnec- 
essary. Special  framing  may  also  be  needed  for  tanks,  stairs  or 
elevators,  and  for  shop  offices,  toilet  or  tool  room  partitions.  Fig. 


STEEL  FEAMING 


155 


Fig.  251. 


WJac/i  ffaffers.  Covered  w/'th  g  "Sheoihlng 
and  Composition  Roofing 


4"Down  Spout 


Fig.  252. 


156 


MILL  BUILDINGS 


r 


Fig.  253. 

249   shows   details   of   anchors,   bolts,   straps,   stirrups,   expansion 
bolts,  etc. 

Large  riveted  sections  must  have  field  splices  so  arranged  that 
no  section  will  have  dimensions  exceeding  those  which  can  be 
accepted  by  the  railroads  or  other  transportation  lines  over  which 
they  are  carried. 

TABLE  XXV. 

MAXIMUM     SHIPPING     DIMENSIONS     ACCEPTED     FOR     TRANS- 
PORTATION BY  THE  RAILROADS  OF  THE  UNITED  STATES. 


Height  above  rail  top  of 
12  ft.  4  ins. 

12  ft.  8  ins. 

13  ft.  0  ins. 
13  ft.  4  ins. 

13  ft.  8  ins. 

14  ft.  0  ins. 


Maximum  width  of 
10  ft.  0  ins. 
9  ft.  9  ins. 
9  ft.  0  ins. 
8  ft.  8  ins. 
8  ft.  4  ins. 
7  ft.  2  ins. 


NOTE.— A  height  of  4  ft.  6  ins.  should  be  allowed  for  car  above  rails. 
The  width  for  loading  is  usually  8  ft.,  but  if  greater,  it  should  be 
specially  noted  before  making. 

COAL  STORAGE   SHEDS. 

Fig.  250  shows  a  design  by  the  author  for  a  coal  storage  shed, 
60  feet  wide  and  473  feet  long.  The  side  foundation  walls  stand 
3  feet  above  the  ground,  and  the  main  side  columns,  which  are 
15  feet  apart,  act  also  as  beams  to  resist  the  side  pressure  of  the 
coal,  and  are  tied  from  the  base  to  the  building  frame.  Inter- 
mediate steel  studs  5  feet  apart  support  the  plank  sheathing. 


STEEL  FEAMING 


157 


Other  coal  shed  designs  are  shown  in  Figs.  251  to  254,  the  last 
being  designed  by  Mr.  F.  M.  Bowman.  Designs  for  boiler  house 
coal  bins  are  illustrated  in  Fig.  255. 


Fig.  254. 


Fig.  255. 


CHAPTER  XV. 


WOOD  FRAMING. 

Timbtf  is  still  much  used,  especially  in  the  South  and  West, 
for  framing  mill  and  factory  buildings,  although  in  the  North 
and  East  its  increased  cost  is  causing  it  to  be  replaced  with  steel 
and  concrete.  It  is  well  known  that  properly  de- 
signed timber  frames  will  collapse  less  quickly  in  a 
fire  than  unprotected  steel,  which  warps  and  bends 
easily  under  heat  and  allows  the,  roof  to  fall. 

In   order  to  be  reasonably  safe  against 
fire,  timber  frames  must  be  designed 
according  to  a  few  well  established 
principles,     which     are     as     fol- 
lows: 


j 


Fig.  256. 


.4. 


WOOD  FRAMING 


159 


(1)  Framing  must  have  the  least  number  of  corners  and  the 
smallest  possible  amount  of  exposed  surface. 

(2)  Floor  beams  must  be  made  in  large  sizes,  5  to   10  feet 
apart,  the  wider  spacing  preferred,  and  must  be  covered  with  at 
least  two  layers  of  matched  or  splined  flooring  plank,  with  two  or 
three  thicknesses  of  asbestos  paper  between  them.     They  must  be 
proportioned  for  weight,  deflection  and  vibration,  and  when  steel 
beams  are  used  with  wood  nailing  pieces  on  their  upper  flange,  the 
steel  must  be  surrounded  with  wire  lath  and  plaster.     (Fig.  256). 

(3)  There  must  be  the  fewest  possible  number  of  floor  open- 
ings, or  preferably  none,  through  which  fire  may  pass,  but  when 
they  are  necessary,  as  at  elevator  openings,  must  be  covered  with 
automatic  closing  doors. 


12*14  7/d\  ^-2*3' ton  Keys 


(4)  Stairways  must  be  placed  in  separate  towers  with  fire- 
proof walls,  and  landings  one  inch  below  the  regular  floor  level 
with  door  openings  covered  with  automatic  self-closing  tin-clad  or 
other  fireproof  doors. 

(5)  There  must  be  no  concealed  or  enclosed  spaces  in  the 
walls  or  floors  through  which  fire  can  travel,  the  object  being  to 
leave  all  wood  surface  exposed  so  water  can  be  turned  upon  it  in 
case  of  fire. 

(6)  Ceilings   are   permitted  only  where  heat  endangers  the 
woodwork,  as  over  boilers,  and  they  must  then  be  placed  directly 
against  the  wood  surface  and  around  the  beams  with  the  least 
possible  air  space  between  the  metal  lath  and  the  wood. 


160 


MILL  BUILDINGS 


WOOD  FEAMING 


161 


Fig.  260. 


(7)  Wood  furring  on  walls  is  not  permitted. 

(8)  Wood  must  be   well  seasoned  before  painting,   and  for 
two  or  three  years  should  be  coated  with  nothing  more  impervious 
than  whitewash  or  kalsomine.    Oil  paint  or  varnish  is  not  permitted. 


Intermediate  Rafters  2^0' 
Pur/ins  3'« 3'^ 


Fig.  261. 


162 


MILL  BUILDINGS 


Fig.  262. 

(9)  Partitions   must    be   made   of 
brick,  tile,  concrete,  asbestos  or  sheet 
metal.     Wood    partitions    are    not    al- 
lowed. 

(10)  Windows  exposed  to  fire  from 
adjoining  buildings  must  be  protected 
with  fire  shutters  or  have  wire  glass, 
the    latter    being    preferred.      Lintels 
must  be  of  reinforced  concrete  or  brick 
arch  rather  than  timber. 

(11)  Timber  columns  are  preferred 
to  exposed  cast  iron  or  steel,  and  may 
be  loaded   to   600   pounds  per   square 
inch.    They  may  be  placed  at  20  to  25 
feet  apart. 

(12)  All    floors   must   have    occa- 
sional   scuppers   through   the   wall   at 
floor  level  to  discharge  the  water  in 
case  of  fire.     (Fig.  266). 

(13)  There  must  be  a  complete  and  Fig  263 
well  organized  system  of  fire  protection. 

Wood  roof  covering  may  be  made  as  described  and  illustrated 
in  Chapter  XX.    Trusses  are  made  all  or  partly  of  wood,  combina- 


WOOD  FRAMING 


163 


Detail  Showing  Joirrt'  in  Lwv«r  Chord  with  .Rods  and  Teot  .Plat«. 
Fig.   264. 


Fig.   265. 


164  MILL  BUILDINGS 

tion  trusses  having  timber  rafters  and  struts  with  rods  for  tension 
members.  The  panel  lengths  should  be  such  as  to  give  web  mem- 
bers an  inclination  of  30  to  60  degrees  to  the  horizontal.  Wood 
trusses  weigh  about  the  same  as  steel  ones  of  the  same  strength, 
and  their  weight  is  not  affected  greatly  by  a  variation  in  roof  slope 
from  one-third  to  one-fifth  the  span.  Cambering  the  bottom 
chord  adds  rapidly  to  the  weight  and  cost.  Timber  lengths  and 
sizes  must  frequently  be  used,,  which  can  be  quickly  procured 
from  local  yards,  and  a  large  wood  framed 
building,  designed  by  the  writer,  and  built  com- 
plete, in  forty  days,  had  trusses  and  columns 
made  of  2-inch  planks  bolted  together  in  the 
required  thickness. 

Observing  the  principles  of  simplicity  and 
duplication  will  greatly  cheapen  construction. 
The  general  arrangement  of  the  timber  fram- 
ing with  the  spacing  of  trusses  and  columns, 
should  be  about  the  same  as  outlined  for  steel. 
The  necessary  thickness  of  plank  for  various 
spans  and  loads  is  given  in  Table  XLI.  Fig.  266. 

Floor  beams  in  the  walls  should  bear  on  cast 

iron  wall  boxes  or  plates  (Fig.  273),  with  upper  corners  of  the 
beams  cut  to  a  bevel  as  shown.  In  case  of  fire,  if  the  beams  burn 
through  and  the  floor  falls,  it  will  not  carry  the  wall  in  with  it. 
When  wood  beams  are  large,  they  may  be  made  in  two  pieces. 
(Fig.  273a)  doweled  together,  with  a  small  ventilated  air  space 
at  the  center  to  prevent  dry  rot.  Other  details  of  wood  floors  are 
as  described  in  Chapters  XX  and  XXI. 

Columns  are  usually  of  hard  pine,  bored  with  a  IJ-inch  auger 
hole  through  the  center,  with  J-inch  ventilation  hole  at  the  top  and 
bottom.  Square  columns  are  25%  stronger  than  round  ones  of 
the  same  thickness,  and  their  corners  should  be  rounded  to  a 
j-inch  radius.  Protection  against  fire  must  be  secured  by  automatic 
sprinkling  systems  on  the  ceilings,  and  standpipes  in  the  stair 
towers  with  hose  attachment  to  each  story.  Water  must  be  taken 
from  two  separate  sources.  In  addition  to  these,  fire  pails  and 
hand  extinguishers  should  be  freely  placed  about,  and  the  occu- 
pants drilled  in  their  use. 

The  cost  of  wood  construction  is  given  in  Chapter  VII. 

Figs.  256-272  illustrate  typical  and  recent  details  of  timber 
framing  for  factory  buildings. 


WOOD  FRAMING 


165 


166 


MILL  BUILDINGS 


Cl.  Ogee  Washers 

"t—  - 

•34"  Bolts . 


fing 


I0ak  Splice. 

Fig.  268. 


Fig.  209 


Fig.   270. 


WOOD  FEAMING 


167 


I  Bolts  I'Bohs'  W|Sfl .... 

iiff'fitkr        •/fC'Cx°        *""          /4'xS'Pinefiller 


k-      :|:    "w  >: 


°RQd  Upset.      


Purlins    for  Car  Machine  Shop 

Fig.  272. 


Fig.  273. 


CHAPTER  XVI. 

CONCRETE  FRAMING. 

Several  comprehensive  books  on  concrete  building  construction 
have  been  written  and  only  its  application  to  mill  buildings  is  given 
here.  The  material  is  well  suited  for  manufacturing  buildings,  as 
it  is  fireproof,  durable,  free  from  vibrations,  and  the  concrete 
materials  can  be  quickly  and  easily  procured.  Money  spent  in 
building  may  be  paid  to  local  people  instead  of  to  others  at  a  dis- 
tance, as  for  structural  steel.  Delays  in  waiting  for  structural  steel 
are  avoided,  and  a  building  can  generally  be  more  quickly  erected 
in  reinforced  concrete.  Insurance  charges  on  concrete  buildings 
are  small,  usually  not  exceeding  15  cents  per  $100.  Reinforced 
concrete  buildings  are  cheaper  than  steel  and  cost  only  a  little 
more  than  wood,  the  relative  costs  being  given  in  Part  I.  Wood 
construction  is  generally  limited  to  six  stories,  but  concrete  can 
be  carried  to  a  greater  height.  In  case  of  fire,  water  does  not 
leak  through  the  floor  and  injure  goods  in  the  lower  stories,  which 
may  occur  with  wood  floors. 

ADHESION  AND  BOND. 

Rich  cement  concrete  in  which  iron  or  steel  is  imbedded  has 
an  adhesion  thereto  of  500  to  600  pounds  per  square  inch  of  exposed 
surface.  Adhesion  of  concrete  to  metal  occurs  only  when  the 
metal  is  thoroughly  imbedded  and  the  concrete  has  opportunity  to 
surround  and  grip  the  bars,  but  not  when  simply  lying  in  contact 
with  the  metal. 

It  has  been  proven  by  numerous  experiments  that  concrete 
adheres  as  securely  to  smooth  rods  as  it  does  to  rough  ones.  Fre- 
quent and  continued  shocks  and  vibrations  tend  to  destroy  the 
union  between  the  two  materials,  and  experiments  show  that  con- 
tinuous watersoaking  from  six  to  twelve  months  reduces  the 
adhesion  by  about  50%.  Poor  workmanship  in  placing  and 
ramming  the  concrete  is  also  probable,  and  it  is,  therefore,  desir- 
able to  use  rough  or  twisted  reinforcing  rods,  so  the  bar  will  have 
a  mechanical  grip  on  the  concrete  in  addition  to  its  adhesion. 

168 


CONCRETE  FRAMING  169 

When  this  roughening  of  the  bar  is  secured  without  reducing  its 
cross  section,  the  whole  area  is  then  available  in  tension,  and  no 
strength  is  lost.  Roughening  the  bars  can  therefore  do  no  harm, 
and  it  may  be  the  source  of  extra  strength. 

METAL  REINFORCEMENT. 

There  is  no  sufficient  reason  from  a  scientific  standpoint,  for 
the  use  of  high  tension  bars  or  rods  for  concrete  reinforcement. 
After  years  of  investigation  and  experiment,  brittle  metal  was 
discarded  for  structural  use,  and  the  only  reason  for  a  return  to 
high  tension  bars  now,  is  a  commercial  one  and  not  scientific.  It 
is  well  known  that  in  rerolling  bars  to  produce  surface  roughening, 
the  tensile  strength  of  the  metal  is  increased.  Instead  of  admit- 
ting the  inferiority  of  the  bars,  interested  parties  have  endeavored 
to  explain  that  this  increase  in  tensile  strength  and  corresponding 
decrease  in  ductility  is  a  benefit.  Medium  steel  with  an  elastic 
limit  of  32,000  pounds  per  square  inch^  and  soft  steel  with  a  corre- 
sponding elastic  limit  of  28,000  pounds  per  square  inch,  are  proper 
grades  of  metal  for  all  ordinary  concrete  reinforcement.  These 
may  safely  be  stressed  up  to  half  their  elastic  limit  under  working 
loads. 

MONOLITHIC    OE    SEPARATELY    MOLDED    MEMBERS. 

The  present  tendency  in  concrete  construction  appears  to  be 
towards  the  use  of  separately  molded  members.  The  objection  to 
the  method  is  the  difficulty  of  handling  and  erecting  the  heavy 
blocks,  but  this  is  overcome  by  the  use  of  a  derrick  car.  The  sepa- 
rately molded  members  (Figs.  274,  275  and  276)  contain  slightly 
more  reinforcing  steel,  and  have  the  extra  cost  of  erection,  but 
nearly  all  the  expense  of  forms  and  carpenter  labor  is  avoided. 
The  shop  floor  may  first  be  laid  and  used  as  a  molding  platform 
for  the  members,  or  a  separate  one  adjoining  the  shop  may  be  laid 
especially  for  the  purpose. 

One  set  of  forms  will  serve  to  cast  100  pieces  or  more,  or  previ- 
ously made  concrete  members  properly  placed  can  be  used  instead. 
Pieces  are  jointed  with  neat  cement,  and  where  bolting  is  needed, 
as  when  girders  rest  on  columns,  pipes  are  cast  into  the  concrete 
in  the  right  positions.  Four-inch  slabs  cast  in  this  manner,  cost 
as  follows : 


170 


MILL  BUILDINGS 
TABLE  XXVI. 


Steel    $2.36  per  100  sq.  ft.  or  30     %  of  total  cost 

Concrete  material    2.55  per  100  sq.  ft.  or  32     %  of  total  cost 

Carpenter    labor    59  per  100  sq.  ft.  or  7V2  %  of  total  cost 

Labor,  mixing  and  placing 56  per  100  sq.  ft.  or  7     %  of  total  cost 

Erection    1.86  per  100  sq.  ft.  or  23% %  of  total  cost 


$7.91 


100     % 


pg- 


'N  xw£^Kj/6.»-;^w  Floor  L 

Elevation    of     Side    Wall 

Fig.   274. 


1 

«   |e 

R 

i     R 

RS 
1 

X  —  ' 

f 

L 

_i_ 

i 

J 

s 

!  i 

*~ 

C 

> 

3 

i 

! 
! 

w 

e  4^'  * 

W 

W 

i 

75* 

¥ 

1 

B 

f 

Base  Cost  in 

°/ace 

nJ^ 

TK-h".1.-'.:.- 


:;^r-^v:  .    --    .    /-:: .-:      -    -rv:-:-:^! 

k 


Details      of      Slabs 
Forming      Side       Wall 


Fig.  275. 

TYPE  OF  CONSTRUCTION. 

A  very  convenient  type  of  construction  for  shops  and  mills,  is 
one  where  columns,  sills,  lintels,  foundations,  floors  and  beams,  are 
made  of  reinforced  concrete,  and  trusses  and  lieavv  o-irders  of  steel, 


CONCEETE  FRAMING 


171 


Fig.  277.  Trusses  are  sometimes  made  in  reinforced  concrete,  but 
they  are  clumsy  and  the  form  work  is  expensive.  Heavy  girders 
such  as  those  carrying  cranes  which  are  subject  to  shock,  are  more 
reliable  and  smaller  in  steel.  Wall  panels  between  the  columns 
may  be  filled  with  brick  or  concrete,  or  a  combination  of  the  two 


Details   of   Roof  Slab*. 


teg^^^  ZV& 


?•*•**•*• 


•  Holt  for  Col.  Conn. 


,s       .     .    ":??.-....         :,;,.  ,. ;•.<?•.-  .    ; .:';; .,;;.;..]'» 

??. ^, J 

>6irder 

Fig.   276. 


Fig.   277*. 

materials.  The  concrete  columns  are  reinforced  with  light  angles 
strong  enough  to  support  the  other  framing  without  roof  covering, 
during  erection.  Floor  beams  or  light  girders  are  also  reinforced 
with  structural  shapes  (Fig.  278),  heavy  enough  to  support  a 
temporary  floor  and  to  brace  the  columns  before  the  concrete  is 
placed.  The  steel  frame  can  be  completely  jointed  before  placing 


'Atlas  Portland  Cement  Co. 


172 


MILL  BUILDINGS 


any  concrete,  thus  insuring  connections.  A  very  pleasing  exterior 
is  produced  by  facing  the  wall  surface  with  4  inches  of  buff  or  yel- 
low brick,  anchored  to  the  concrete,  or  a  finish  of  Portland  cement 
and  white  sand  and  quartz.  Large  buildings  of  this  type  can  be 
erected  at  the  rate  of  about  100,000  cubic  feet  of  building  contents 
per  week. 


Connections  of 
Beams  to  Girders. 


Fig.  278. 


FLOCKS  AND  EOOFS. 

Floors  and  roofs  may  be  made  of  the  same  general  type  of 
construction  with  the  beams  in  the  roof  farther  apart.  Slabs  are 
reinforced  with  expanded  metal,  wire  mesh  or  rods,  and  the  thick- 
ness of  slab  and  area  of  reinforcing  steel  is  found  from  the  author's 
formulas : 


M 
D  =   J- 

\      1,000 
D 


A  = 


12 


Where  D  is  the  depth  of  slag  in  inches 

M,  the  bending  moment  in  inch  pounds  per  foot  width  of  slab,  and 
A,  the  area  of  steel  in  square  inches  per  foot  width. 

When  the  arrangement  of  beams  will  permit,  it  is  economical 
to  use  slab  reinforcement  in  two  directions  at  right  angles  to  each 
other. 

The  cost  per  square  foot  of  reinforced  concrete  slabs  6  inches 
thick  is  as  follows: 


CONCRETE  FRAMING 


173 


7  Jon  Crane '  j  • 
Truss -\' 


-—II8-0 > 

Fig.  279. 


Concrete  costs   12  cents  per  sq.  ft. 

Steel          5  cents  per  sq.  it. 

Centers '!.!.!!!..!.......'-' 8  cents  Per  scl-  f *• 

Total    _  25  cents  per  sq.  ft 

Flat  slab  floors  without 
beams  in  either  direction  re- 
quire about  40  per  cent 
more  steel  than  floors  with 
beams  and  thin  slabs,  but 
this  extra  cost  is  partly  off- 
set by  the  low  cost  of  cen- 
ters. 

An  unusual  form  of  shop 
roof  is  shown  in  Fig.  279, 
the  roof  slab  being  made  in 
the  form  of  an  arch,  4 

inches  thick  at  the  crown  and  10  inches  at  the  haunches.  The  arch 
thrusts  against  skewbacks  at  the  sides,  which  are  tied  together  at 
intervals  with  rods.  The  usual  concrete  slab  roof  construction  on 
steel  trusses  is  illustrated  in  Fig.  280. 

Concrete  and  steel  cost 45  cents  per  lin.  ft. 

Forms    25  cents  per  lin.  ft. 

Total    70  cents  per  lin.  ft. 

Concrete  girders,  12  X  20  inches,  cost : 

Concrete   and   steel 60  cents  per  lin.  ft. 

Forms    35  cents  per  lin.  ft. 

Total    95 

Girders,  15  X  22  inches,  with  light  structural  reinforcing,  18 
feet  long  and  16  feet  apart,  to  carry  an  imposed  load  of  125  pounds 
per  square  foot,  are  shown  in  Fig.  281.  The  steel  framework 
erected  in  place  costs  $65  to  $70  per  ton.  Separately  molded  floor 
beams  in  I  forms  (Fig.  282)  are  used  and  have  the  merit  of 
lighter  weight  than  solid  ones. 


COLUMNS. 

The  practice  in  designing  columns  is  to  use  plain  concrete 
columns  with  four  to  eight  reinforcing  rods  (Fig  283),  for  sizes 
up,  to  16  or  18  inches  square,  the  concrete  being  loaded  to  500 


174 


MILL  BUILDINGS 


pounds  per  square  inch,  neglecting  the  strength  of  the  metal  in 
compression.  If  this  form  would  require  a  size  exceeding  about 
18  inches  square,  a  hooped  or  wound  column  may  then  be  used 
instead  (Figs.  284  and  285)  with  the  part  inside  the  winding 
loaded  to  1,000  pounds  per  square  inch,  at  the  same  time  consid- 
ering the  bearing  value  of  the  steel  in  compression.  Figure  285 


Fig.  280. 


Fig.  281. 


Fig.   282. 


Fig.  283. 


Fig.  284. 


Fig.  285. 


with  laced  or  battened  angles,  is  cheaper  than  284  with  circular 
winding. 

The  cost  per  vertical  foot  of  a  column  18x18  (Fig.  284),  is  as 
follows : 


CONCRETE  FRAMING 


175 


Concrete,    18    X    18   in 55  cents  per  vertical  ft. 

Steel    75  cents  per  vertical  ft. 

Forms  50  cents  per  vertical  ft. 


Total    $1.80 


per  vertical  ft. 


An  approximate  cubic  foot  cost  for  reinforced  concrete  columns 

and  girders  is  as  follows: 

Concrete  costs 25  cents  per  cu.  ft. 

Steel    15  cents  per  cu.  ft. 

Forms  and  form  labor 25  cents  per  cu.  ft. 

Total    65  cents  per  cu.  ft. 


Fig.  286. 

Eeinforced  concrete,  including  steel,  costs  about  $12  per  cubic 
yard  in  place,  and  forms  and  scaffolding  about  $5  per  cubic  yard 
additional,  or  $17  total.  Concrete  framing,  including  slabs,  beams 
and  columns  only,  costs  from  35  to  55  cents  per  square  foot  of  floor 
area,  while  complete  reinforced  concrete  buildings,  including  light- 
ing, heating,  plumbing,  and  stairs  or  elevators,  but  without  plas- 
tering or  partitions,  cost  from  6  to  12  cents  per  cubic  foot  of 
contents. 

Figs.  286,  287  and  288  show  three  views  of  a  model  reinforced 
concrete  mill  building,  60  feet  wide,  125  feet  long  and  40  feet 
clear  height  at  the  center,  erected  in  New  Jersey  in  1908.  It  has 
a  complete  frame  of  reinforced  concrete,  the  exterior  being  enclosed 


176 


MILL  BUILDINGS 


Fig.  287. 


Fig.  288. 


CONCRETE  FRAMING 


177 


with  molded  concrete  blocks.  It  was  designed  by  Mr.  A.  N.  Hazen, 
Engineer  for  the  Expanded  Metal  Engineering  Company  of  New 
York,  and  costs  complete  less  than  6  cents  per  cubic  foot.  Fig.  289 
illustrates  the  method  of  erecting  the  roof. 

Fig.  277  is  a  section  of  a  machine  shop  erected  in  Ohio,  107 
feet  wide  and  256  feet  long,  with  columns  16  feet  apart  longi- 
tudinally. The  walls,  floors  and  columns  are  of  reinforced  con- 
crete, with  steel  roof  trusses  and  crane  girders.  Columns  have 
concrete  brackets,  supporting  girders  for  a  ten-ton  traveling  crane. 


Fig.   289. 


Fig.  290. 


178 


MILL  BUILDINGS 


The  floor  is  proportioned  to  sustain  225  pounds  per  square  foot, 
and  the  slabs  are  8  inches  thick,  supported  on  thin  and  deep  con- 
crete beams,  16  feet  apart.  Until  the  center  traveling  crane  is 
installed,  a  temporary  wood  floor  is  used  in  the  middle  bay.  The 


—  —  -  ......  —  25'0"-  .......  ------  .....  - 


-----  ^5'o*~  -------  ......... 


Fig.  291. 


^— iyn 


»(« 30'0» »• 

Fig.   292. 


work  of  constructing  and  completing  the  building  occupied  less 
than  two  months'  time. 

Figs.  290  and  291  show  concrete  framing  details  for  shop 
buildings  with  traveling  cranes,  while  Fig.  292  is  an  engine  house 
with  separate  molded  members,  at  Waterbury,  Conn. 


CHAPTER  XVII. 

NORTHERN  LIGHT  ROOF  FRAMING,  IN  WOOD,  STEEL 
AND  CONCRETE. 

Northern  light  roofs  were  introduced  into  the  United  States 
about  the  year  1870,  but  were  not  very  generally  adopted  except- 
ing for  cotton  mills  until  twenty  years  later,  when  their  use  was 
extended  to  other  lines  of  manufacture. 

Their  chief  advantage  is  that  clear  north  light  from  the  sky 
can  be  received  without  admitting  direct  sunshine  or  using  window 
shades,  and  work  benches  can  be  arranged  crossways  of  the  floor, 
as  well  as  longitudinally  against  the  walls.  Abundant  light  free 
from  shadows  is  necessary  to  produce  the  greatest  quantity  and 
the  best  quality  of  work.  It  is  easy  in  case  of  fire  for  employees 
to  escape  through  the  windows  of  one-story  shops,  and  on  a 
single  floor,  goods  can  be  more  easily  transferred  from  one  place 
to  another.  Single  story,  square  buildings  have  less  than  half  the 
wall  surface  of  long  narrow  buildings  40  or  50  feet  wide  of  the  same 
floor  area. 

The  objection  to  northern  light  roofs  is  their  greater  cost  and 
liability  to  leak  at  the  gutters,  especially  in  cold  or  freezing  weather. 
The  worst  leaks  occur  when  water  collects  under  ice  and  snow  in 
the  gutter,  and  is  forced  or  drawn  up  over  the  flashing,  or  when 
gutters  freeze  up  solid  and  burst.  Like  other  low  buildings,  they 
are  harder  to  ventilate  than  higher  ones,  and  the  exterior  tempera- 
ture is  transmitted  through,  and  radiated  from  the  under  side 
of  roof,  producing  draughts  and  physical  injury  to  the  occupants. 
Another  objection  is  that  condensation  from  the  roof  windows 
may  drip  and  cause  injury.  The  area  and  cost  of  northern  light 
roofs  exceeds  that  of  ordinary  double  pitch  roofs  without  skylight 
by  40  to  60%,  which  is  about  the  extra  area  and  cost  of  the  slop- 
ing windows.  In  northern  latitudes,  snow  may  occasionally  need 
removing  from  the  roof,  for  it  may  drift  into  the  valleys  and 
obstruct  light,  but  records  show  that  this  condition  is  not  fre- 
quent. The  unsymmetrical  form  of  these  roofs  is  not  pleasing, 
but  this  may  be  partially  remedied  by  extending  the  gable  walls 
high  enough  to  conceal  them. 

Northern  light  roofs  are  suitable  chiefly  for  wide  one-story 

179 


180  MILL  BUILDINGS 

buildings,  but  their  extra  expense  is  unwarranted  on  high  build- 
ings less  than  about  100  feet  in  width,  where  abundant  light  can 
be  had  from  the  side  wall  windows.  Multi-story  buildings  have 
a  less  cost  per  square  foot  of  floor  .area  than  single  story  shops, 
and  when  loads  and  other  conditions  will  permit,  should  generally 
be  used  with  the  greatest  available  area  of  wall  windows,  before 
resorting  to  the  more  expensive  type  of  single  story  saw  tooth 
roofs. 

EOOF  OUTLINES. 

Glass  should  face  directly  or  nearly  north,  and  to  receive  the 
clearest  light,  should  be  inclined  to  the  vertical  as  steep  as  possible 
without  admitting  sunshine  in  the  longest  days  of  summer.  An 
angle  of  25  or  30  degrees  to  the  vertical  is  usually  satisfactory, 
though  the  slope  varies  with  the  latitude,  being  6  degrees  nearer 
the  vertical  in  the  southern  states  than  in  the  north.  Windows  are 
often  placed  vertical  for  convenience  in  framing,  weighting  the 
sash  and  making  them  water  tight,  but  vertical  windows  admit 
less  light  and  make  a  greater  roof  area  to  cover.  The  south  roof 
slope  should  be  great  enough  to  shed  water,  and  to  comply  with 
the  required  pitch  for  the  chosen  roof  covering  as  given  in  Table 
XII,  but  it  should  not  be  so  steep  as  to  prevent  light  from  reach- 
ing the  floor  or  make  the  cost  of  windows  excessive.  Gutters 
should  be  one  or  two  feet  wide  to  prevent  clogging  and  bursting, 
but  if  wider,  shadows  or  poorer  light  under  them  will  result, 
Ridges  are  generally  horizontal,  but  in  some  cases  (Fig.  323)  both 
ridge  and  gutter  are  sloped  to  the  sides. 

When  a  roof  has  a  series  of  saw  tooth  sections,  it  is  convenient 
to  stop  the  sloping  part  or  monitor  a  few  feet  from  either  side, 
leaving  a  flat  walk,  to  permit  access  to  the  valleys  without  climb- 
ing over  the  ridges. 

Some  outlines  of  northern  light  roofs  are  shown  in  Figs.  96  to 
105,  the  semi-sawtooth  of  101  having  the  disadvantage  of  forming 
dark  places  or  shadows  under  the  flat  part  or  gutters. 

WINDOW  AREA. 

The  general  rule  for  area  of  roof  light  is  to  cover  25  to  50% 
of  the  roof  with  glass,  the  amount  depending  on  the  degree  of 
detail  work  to  be  performed  in  the  building.  The  shop  will 
usually  be  sufficiently  lighted  when  the  height  of  windows  is  one- 
third  to  one-fourth  of  the  saw  tooth  span.  If  the  under  side  of 
the  south  slope  is  painted  white,  lighting  will  be  improved  by 


NORTHERN  LIGHT  ROOF  FRAMING 


181 


reflecting  it  to  the  floor.    A  design  shown  in  Fig.  294  has  skylight 
on  the  south  slope  in  addition  to  the  north  light  windows. 

GUTTERS  AND  CONDUCTOES. 

An  objection  to  northern  light  roofs  is  the  danger  of  leakage 
from  the  gutters.  If  less  than  1  or  2  feet  in  width,  gutters  are 
liable  to  be  clogged  with  snow  and  ice,  and  if  wider  than  3  or  4 


\ 

/ 

\ 

/ 

\ 

/ 

\ 

/ 

Fig.   293. 


Fig.   294. 


Fig.  295. 


Fig.  296. 


Fig.  297. 


Fig.   298. 


Fig.   301. 


182 


MILL  BUILDINGS 


feet,  the  uniformity  of  interior  lighting  is  affected.  Minimum 
and  maximum  gutter  widths  should  therefore  be  1  to  4  feet.  To 
prevent  injuring  or  breaking  gutters  when  cleaning  them  or  remov- 
ing snow,  some  designers  have  laid  a  board  walk  in  them  with 
open  slats,  but  it  is  not  recommended,  for  the  walk  tends  to 
collect  and  hold  snow  and  dirt.  Freezing  can  be  partly  or  entirely 
avoided  by  running  lines  of  steam  pipes  beneath  the  gutter  in  the 
shop,  which  serve  also  as  part  of  the  general  heating  system.  Some 
shops  place  one-third  of  the  heating  pipes  there.  Change  of  tem- 
perature causes  metal  gutters  to  contract  and  expand,  resulting  in 
cracks  and  leaks.  To  prevent  these  cracks,  cast  iron  gutters  were 


Fig.  302. 

formerly  used,  but  they  are  heavy  and  expensive,  and  the  modern 
and  better  way  is  to  use  wider  ones,  covered  with  flashing  or  the 
regular  roofing. 

Gutters  should  pitch  ^  or  J  inch  per  foot  to  interior  downspouts 
rather  than  to  exterior  ones,  for  when  placed  outside  the  building, 
conductor  pipes  freeze  up  in  cold  weather.  Down  spouts  should 
be  placed  40  to  50  feet  apart  at  the  columns,  and  should  connect 
to  drains  leading  to  a  reservoir  for  plant  use,  or  to  the  sewer.  A 
3-inch  pipe  will  drain  1,000  square  feet  of  roof,  and  the  pipe 
should  be  protected  at  the  top  by  a  wire  screen  or  basket  (Fig.  311). 

COLUMN  SPACING. 

The  cost  of  roof  framing  depends  largely  on  the  column  spac- 
ing. If  long  spans  and  open  floor  space  is  needed,  the  cost  of 
framing  will  be  increased.  For  many  kinds  of  manufacture,  col- 


NOKTEEEN  LIGHT  EOOF  FRAMING 


183 


umns  are  convenient  rather  than  otherwise,  and  will  result  in 
much  saving  in  the  roof  trusses.  Pipe  columns,  either  plain  or 
filled  with  concrete,  are  much  used  for  the  light  roof  loads  in 
saw  tooth  buildings,  and  are  quite  economical,  though  inconvenient 
for  connections. 


Fig.  303. 


Fig.  304. 


184 


MILL  BUILDINGS 
FRAMING. 


The  kind  of  framing  for  northern  light  roofs  depends  upon  the 
permissible  number  of  columns,  the  length  of  spans,  amount  of 
window  area  and  the  roof  outline  as  determined,  by  preliminary 
investigation.  Glass  should  face  the  north,  but  ridges  may  lie 
either  transversely  or  longitudinally  of  the  building.  The  differ- 
ent kinds  of  northern  light  roof  framing  may  be  classified  under 
three  headings  as  follows : 


Fig.  305. 


(a)  Trusses  on  columns  with  rafters  in  the  slope  of  roof, 

(b)  Eafters  supported  on  longitudinal  beams   (Fig.  296)   or 

trusses   (Fig.  298). 

(c)  Eafters     supported     on     transverse    beams     or     trusses 

(Fig.  299). 

Class  (a)  are  suitable  for  spans  not  exceeding  60  feet,  and 
preferably  not  over  40  feet,  but  (b)  and  (c)  can  be  used  for  much 
greater  lengths.  Class  (c)  has  the  disadvantage  that  the  truss  fram- 
ing lies  across  the  windows,  and  casts  shadows  on  the  floor.  Wher- 
ever possible,  framing  should  be  arranged  to  avoid  these  shadows, 
and  in  some  trusses,  rods  are  used  instead  of  riveted  members  for 
bottom  chords,  but  stiff  chords  are  more  convenient  for  shaft- 


NOKTHEBN  LIGHT  EOOF  FRAMING 


185 


ing.  Framing  across  the  windows  is  more  objectionable  than 
parallel  with  the  trusses,  but  in  either  direction  below  the  window 
level,  shadows,  and  light  obstruction  may  result.  Saw  tooth  roofs 
should  have  a  clear  height  beneath  the  trusses,  of  12  feet  and 


Fig.  306. 


Fig.   307. 


186 


MILL  BUILDINGS 


preferably  more.  Low  rooms  are  easier  to  heat,  and  the  windows 
are  down  nearer  to  the  work,  but  ventilation  is  poor  and  heat 
excessive  in  summertime.  When  the  small  tools  of  machine  and 
erecting  shops  are  placed  all  at  one  side  of  the  erecting  floor  the 
need  of  crossing  back  and  forth  under  the  cranes  is  avoided  and 
time  is  saved. 


Fig.  308. 


NOETHEEN  LIGHT  EOOF  FEAMING 


187 


*_4-'' 

0 


Fig.  310. 


A  saw  tooth  roof  of  novel  design,  erected  for  a  large  plant  in 
Belgium,  is  shown  in  Fig.  313.  Trusses  are  three-hinged,  and 

alternate  ones  rest  on  braced  piers. 
They  have  spans  of  53  feet  and  a 
crown  angle  of  90  degrees. 

A  design  made  in  1898  by  the 
author  with  a  clear  span  of  58  feet 
and  trusses  12  feet  6  inches  apart, 
is  shown  in  Fig.  299.  It  has  the 
advantage  of  no  inside  columns,  but 
has  lattice  trusses  crossing  the  win- 
dows. A  similar  design  for  a  saw 
tooth  roof  on  the  side  bays  of  a  loco- 
motive shop  with  windows  vertical, 
is  illustrated  in  Figs.  304  and  305. 

The  saw  tooth  lighting  of  Fig. 
323  consists  of  transverse  north  light 
monitors  over  alternate  bays,  sup- 
ported on  lattice  trusses  150  feet  be- 
tween columns.  The  arrangement 
affects  only  the  monitor  frames  but 
Fig.  311.  not  the  trusses,  which  are  of  usual 

construction. 

CONDENSATION. 

Condensation  forms  when  the  inner  and  outer  atmospheres  are 
at  different  temperatures.  To  prevent  condensation,  there  should 


188 


MILL  BUILDINGS 


Pccrt  Front  Elevation. 

Fig.  312. 


NORTHERN  LIGHT  ROOF  FRAMING 


189 


Fig.  314. 


Fig.  Sir, 


Fig.   316. 


190 


MILL  BUILDINGS 


be  no  heat  conducting  connection  between  the  inside  and  outside 
air.  In  cold  climates,  windows  should  be  double  glazed,  and  metal 
ventilators  should  have  double  walls  with  air  space  between  (Fig. 
516).  Skylight  and  window  bars  are  sometimes  made  with  ventila- 
tion holes  (Fig.  543),  which  assist  in  maintaining  a  uniform  tem- 
perature on  both  sides  of  the  bar.  Wood  framing  is  less  liable 


Fig.  317. 


xGalv  Iron  flashing 
/  f  5  ply  roofm^  plus  extra  layer  of  f«ll 
'    ;     No  V>  Galv  iron 


Fig.   318. 

to  collect  condensation   than  steel   or  concrete,   and   is   therefore 
sometimes  preferred. 

VENTILATION. 

The  most  effective  ventilation  is  that  secured  from  a  fan  and 
blower  heating  system,  with  ducts  overhead  or  beneath  the  floor. 
In  warm  weather  the  heating  system  is  changed  to  a  cooling  one, 
by  passing  cold  water  through  the  pipes  over  which  the  air  is 
blown. 

Separate  metal  ventilators  with  double  walls  and  weather  vane 


NORTHERN  LIGHT  ROOF  FRAMING 


191 


caps  may  be  placed  on  the  south  slope  near  the  ridge.  They  should 
have  dampers  in  the  shaft  for  closing  the  draft  when  it  is  not 
desired  (Fig.  516). 

Ventilation  may  also  be  secured  by  swinging  all  or  part  of  the 
windows,  though  movable  windows  are  not  desirable,  as  water  is 


Fig.  319. 


Pig.   320. 


liable  to  leak  through  during  driving  storms.  Opening  the  upper 
half  of  alternate  panels  will  give  ample  ventilation,  and  top  hinges 
are  preferable  to  trunnions,  as  joints  are  then  more  easily  flashed. 
End  gables  may  have  fixed  or  movable  louvres  or  swinging  windows. 


192 


MILL  BUILDINGS 


i_       i  v        -    'j  "  -          I 

Expansion  Joint.  —  |^-  Expansion  Joint: 


|<  -------  Transverse.  Roof  Trusses      ---- 

Fig.  321. 


Fig.  322. 


Fig.  323. 


NOKTHEEN  LIGHT  ROOF  FRAMING 
WINDOWS. 


193 


Windows  should  have  clear  white,  rather  than  green  glass,  and 
in  cold  climates  should  be  double  glazed,  the  inner  pane  being 
factory  ribbed,  with  the  smooth  side  exposed  to  view.  In  all 
cases  with  either  single  or  double  glazing,  windows  must  have 
condensation  gutters  (Figs.  309,  318  and  319)  to  prevent  drip- 
ping. Wood  sash  are  cheaper  than  metal  ones,  though  the  latter 


Fig.   324. 


Fig.   325. 


are  fireproof,   and  sloping  sash  should  have  muntins  similar  to 
greenhouse  or  skylight  bars,  with  condensation  gutters. 

Movable  sash  must  be  carefully  designed  and  flashed,  to  pre- 
vent leakage  during  severe  storms  which  usually  blow  from  the 
northeast  or  northwest.  Appliances  for  opening  these  windows  are 
shown  in  Figs.  316,  317  and  322.  No  arrangement  of  windows 
will  make  effective  lighting  unless  the  glass  is  frequently  cleaned. 


194 


MILL  BUILDINGS 


COST. 

The  cost  per  square  foot  of  floor  area  for  a  large  saw  tooth 
shop,  covering  60,000  square  feet  of  ground  is  as  follows: 

Steel  work   33.7  cents  per  sq.  ft.  of  floor  area 

Six-inch  concrete   floor 11.5  cents  per  sq.  ft.  of  floor  area 

Foundation  and  brickwork 10.3  cents  per  sq.  ft.  of  floor  area 

Lumber 14.0  cents  per  sq.  ft.  of  floor  area 

Painting    1.1  cents  per  sq.  ft.  of  floor  area 

Roof   covering    1.1  cents  per  sq.  ft.  of  floor  area 

Sewers    2.0  cents  per  sq.  ft.  of  floor  area 

Miscellaneous 6.3  cents  per  sq.  ft.  of  floor  area 

Total     80.0  cents  per  sq.  ft.  of  floor  area 


\ 


Fig.  326. 


Fig.  327. 


PART  IV 
DETAILS  OF  CONSTRUCTION 


CHAPTER  XVIII. 

FOUNDATIONS  AND  ANCHORAGES. 

The  subject  of  foundations  is  very  extensive  and  will  be  referred 
to  only  briefly,  for  building  the  foundations  of  manufacturing 
plants  will  generally  not  be  difficult.  Unless  in  special  cases,  sites 
will  be  selected  on  which  buildings  can  be  erected  economically, 
and  where  foundations  will  be  comparatively  simple.  There  are 
cases,  however,  where  other  considerations  outweigh  economy  of 
construction,  as  that  of  the  American  Bridge  Company's  plant  at 
Ambridge,  and  the  Lackawanna  Steel  Company's  plant  at  Buffalo. 
The  location  at  Ambridge,  beside  the  river,  was  low  and  required 
much  filling  and  deep  foundations,  while  at  Buffalo  the  plant  was 
built  over  a  swamp,  the  top  of  which  was  excavated  3  feet  and 
the  buildings  supported  on  piles  capped  with  timber  and  concrete. 
Some  of  the  extensive  manufacturing  buildings  at  Sault  Ste.  Marie, 
Ontario,  are  also  built  over  swampy  ground  adjoining  the  source 
of  power,  and  the  new  Steel  Corporation's  buildings  at  Gary, 
Indiana,  on  the  shore  of  Lake  Michigan,  are  built  on  sand,  below 
lake  level,  requiring  a  solid  slab  of  concrete  5  feet  thick  under 
the  entire  area  of  some  of  the  buildings. 

LOADS. 

The  amount  and  character  of  loads  must  be  known  before  pro- 
portioning the  foundations.  To  know  the  loads  definitely,  the 
parts  of  the  building  above  ground,  including  walls,  roofs  and 
floors,  must  be  designed.  Brick  work  weighs  120  pounds  and  con- 
crete 140  pounds  per  cubic  foot,  while  the  weight  of  floors  will 
depend  upon  their  design.  The  live  loads  on  floors,  including  the 
weight  of  machinery  and  material  must  be  separated  from  the 
dead  load,  for  the  effect  of  impact  from  live  loads  must  be  con- 

195 


196  MILL  BUILDINGS 

sidered.  Live  loads  must  be  increased  50  to  100%  for  impact, 
depending  upon  the  extent  of  vibration  from  the  machinery. 
Floors  for  light  machinery  will  have  a  capacity  for  sustaining 
imposed  loads  of  100  to  200  pounds  per  square  foot,  and  those 
for  heavy  machinery,  200  to  400  pounds  per  square  foot,  while 
cupola  or  foundry  floors  where  iron  or  lead  is  piled,  may  be  pro- 
portioned for  500  to  1,000  pounds  per  square  foot.  The  side 
footings  and  foundations  on  tall  narrow  buildings  have  important 
vertical  loads  from  the  overturning  effect  of  wind  on  the  building, 
which  may  be  considered  as  dead  load,  because  it  will  not  ordinarily 
occur  in  conjunction  with  maximum  floor  loads. 


BEARING  POWER  OF  SOILS. 

TABLE  XXVII. 
SAFE  BEARING  PRESSURE  ON  SOIL. 

Hard  rock  on  native  bed 250  tons  per  sq.  ft. 

Ledge  rock    36  tons  per  sq.  ft. 

Hard  pan 8  tons  per  sq.  ft. 

Gravel    5  tons  per  sq.  ft. 

Clean   sand    4  tons  per  sq.  ft. 

Dry  clay    3  tons  per  sq.  ft. 

Wet  clay    2  tons  per  sq.  ft. 

Loam 1  ton    per  sq.  ft. 

The  sustaining  power  of  soils  may  be  increased  by  draining 
the  subsoil  with  tile  drains  or  layers  of  sand  and  gravel,  or  by 
compressing  and  hardening  it.  Greater  supporting  power  is  secured 
by  distributing  the  bearing  over  greater  areas,  with  spread  footings 
of  timber,  steel  or  concrete,  or  by  driving  piles. 

Gravel  and  sand  are  the  best  foundations,  for  they  are  firm 
and  well  drained;  sand  will  sustain  great  loads  if  held  from 
spreading  sideways.  Eock  is  too  hard  and  non-resisting  and  not 
often  found  at  the  surface  on  manufacturing  sites,  while  loam  is 
too  soft  and  unreliable.  Foundations  on  clay  are  greatly  improved 
by  filling  the  foundation  pits  and  trenches  with  a  thick  layer  of 
gravel  and  sand  rammed  in  solid  between  the  trench  side  walls. 
The  size  of  most  building  foundations  is  proportioned  to  load  the 
ground  not  more  than  1  to  2  tons  per  square  foot.  Where  there  is 
any  doubt  about  the  safe  bearing  power  of  the  soil,  soundings 
should  be  made  and  a  small  known  area  tested  by  piling  weights 
upon  it.  An  easy  way  of  sounding  is  to  drive  lengths  of  pipe  into 
the  ground  with  a  water  jet  inside  the  pipe  to  force  out  the  core, 


FOUNDATIONS  AND  ANCHORAGES  197 

a  method  which  was  successfully  used  by  the  author  for  sounding 
to  great  depth  in  the  harbor  at  San  Pedro,  California. 

AREA  ON  SOIL. 

Foundations  are  proportioned  not  to  resist  settling,  but  to 
settle  uniformly  over  the  whole  building  area.  If  some  parts  of 
building  stand  on  rock  and  other  parts  on  yielding  soil,  cracks  in 
the  wall  are  sure  to  result,  for  the  part  on  solid  rock  will  have  no 
settlement,  while  other  parts  will  sink  a  little.  For  this  reason 
partial  rock  foundations  for  manufacturing  buildings  should  be 
avoided.  All  foundation  beds  should  have  as  nearly  as  possible 
the  same  load  per  square  foot.  It  is  just  as  injurious  to  have 
some  parts  of  the  foundation  too  large  as  it  is  to  have  them  too 
small.  If  side  walls  are  used,  care  must  be  taken  that  the  wall 
base  will  not  cover  too  great  an  area  and  make  a  less  pressure  per 
square  foot  on  the  soil  under  the  wall  than  under  interior  columns. 
To  better  secure  even  pressure  on  the  soil,  the  weight  of  side  walls 
is  sometimes  transferred  by  beams  or  arches  to  individual  piers 
under  the  columns  at  the  panel  points. 

SIDE  WALL  FOUNDATIONS. 

A  continuous  foundation  under  side  walls  is  economical  when 
the  columns  of  piers  are  fairly  close  together,  but  for  longer  panels, 
separate  piers  are  preferable,  with  a  light  base  between  them  if 
necessary,  to  support  the  curtain  wall. 

PIERS. 

Hard  brick  or  concrete  is  well  suited  for  building  isolated 
piers,  producing  generally  a  better  bond  than  can  be  secured  with 
stone;  but  if  stone  is  used,  it  must  be  laid  flat  on  its  original  bed 
and  built  solid  through  the  pier,  rather  than  by  making  the 
exterior  of  dressed  stone  with  a  rubble  center.  Concrete  piers  are 
most  economical  when  laid  in  courses  12  to  18  inches  thick,  with 
stepped  or  offset  edges  similar  to  stone  piers  (Fig.  343).  for  a  few 
regular  size  form  boxes  can  then  be  used  for  several  piers.  Another 
common  form  box,  though  not  as  economical  as  the  one  just  de- 
scribed, is  made  in  the  shape  of  a  truncated  cone  with  straight 
sloping  sides  (Fig.  341),  and  whether  the  sides  are  sloped  or 
offset,  the  angle  of  slope  should  not  be  less  than  60  degrees  to  the 
horizontal,  for  if  greater,  the  offsets  are  liable  to  crack  and  not 
distribute  the  pressure  evenly  on  the  base.  Pier  caps  should  be 


198 


MILL  BUILDINGS 


large  enough  to  allow  at  least  6  inches  from  the  boit  holes  to  the 
edges  of  the  stone,  without  producing  a  pressure  on  the  pier  below 
the  cap  greater  than  200  pounds  per  square  inch  on  brick  and 
250  pounds  per  square  inch  on  concrete.  Unless  for  very  small 
piers,  dressed  caps  of  natural  or  artificial  stone  are  preferable,  the 
thickness  of  which  should  be  from  one-third  to  one-fifth  their 
greatest  length  (Fig.  342).  All  piers  and  foundations  should 
extend  at  least  6  inches  below  the  frost  line,  and  not  less  than 


Set  Bolt  Anchorage. 
Fig.  341. 


Rough  Bolt  Anchorage. 
Fig.   342. 


Fig.  343. 


3  feet  below  the  natural  ground  surface,  and  generally  for  shops 
without  much  floor  filling,  will  be  from  4  to  5  feet  in  height. 

Piers  with  spread  footings  are  economical  and  much  used,  and 
are  made  with  a  grillage  of  steel  beams,  old  rails,  reinforced  con- 
crete or  heavy  timber.  The  pressure  on  the  soil  under  these  piers 
is  distributed  by  the  bending  resistance  of  the  lower  courses. 
Reinforced  concrete  spread  footings  are  more  used  and  cheaper 
than  those  made  with  heavy  steel,  and  more  durable  than  timber, 
though  in  many  cases,  particularly  for  light  foundations,  spread 
footings  made  with  double  courses  of  timber  laid  crosswise  to  each 
other,  are  more  economical  and  quite  as  satisfactory.  When  tim- 
ber is  used,  however,  it  must  be  placed  below  water  where  it  will 
be  always  submerged,  or  must  be  always  dry  and  should  then  be 
coated  with  lime  or  tar  as  a  preservative.  The  dimensions  of 
spread  footings  in  steel  and  reinforced  concrete  can  be  obtained 
from  any  steel  or  concrete  handbook,  or  can  very  easily  be  computed. 


FOUNDATIONS  AND  ANCHORAGES 


199 


MACHINERY  FOUNDATIONS. 

Machinery  foundations  are  often  quite  different  from  piers 
supporting  static  loads,  for  the  former  must  resist  the  action  of 
continuous  vibration  without  injury,  and  heavy  anchor  bolts  are 
generally  needed  to  fasten  the  machines  securely  to  the  base  and 
prevent  lifting  or  lateral  movement.  Solid  masonry,  even  though 
of  great  size,  under  a  heavy  steam  hammer  would  soon  be  shattered, 
for  it  offers  no  spring  or  elasticity.  Piers  all  or  partially  of  timber 
are  the  best  for  this  purpose,  and  machines  of  any  kind  are  found 
to  run  more  smoothly  on  timber  than  on  stone  (Figs.  344  and  345). 

PILES. 

Piles  are  needed  under  piers  and  foundations  when  the  soil  is 
too  soft  to  sustain  a  less  load  than  one  or  two  tons  per  square  foot. 
Building  sites  are  often  chosen  adjoining  deep  water  and  well 
located  for  shipping,  but  which  are  not  economical  in  foundations. 
The  cost  of  shipping  is  continuous  and  often  more  important  than 
the  first  cost  of  the  plant,  and  sites  are  sometimes  chosen  con- 
venient for  shipping  but  requiring  extra  expense  on  the  foun- 
dations. 

Wooden  piles  can  be  driven  2%  to  3  feet  apart,  and  will  generally 
safely  sustain  loads  of  10  to  20  tons  each.  The  most  approved 
formula  for  the  safe  load  on  piles  is : 


DH 


Safe  load  in  tons  = 


1000    (1+P) 


Where  D  is  the  drop  of  hammer  in  feet, 

H  the  weight  of  hammer  in  pounds,  and 

P  the  penetration  of  the  pile  in  inches  under  the  last  blow. 


Fig.  344. 


Fig.  345. 


200  MILL  BUILDINGS 

Piles  should  be  capped  with  heavy  timber  or  concrete,  and 
when  concrete  is  used  it  should  cover  and  surround  the  pile  heads 
for  a  depth  of  6  to  12  inches.  When  timber  is  always  below  water, 
it  is  permanently  preserved,  and  this  condition  is  preferable  to 
having  it  alternately  wet  and  dry,  for  timber  then  rots  rapidly. 

Piles  are  frequently  pointed  to  facilitate  driving,  and  they  are 
sometimes  provided  with  cast  iron  points,  though  this  adds  expense 
and  is  often  of  little  benefit.  When  there  is  a  tendency  to  split 
under  the  hammer,  the  piles  should  have  wrought  iron  rings  fitted 
tightly  over  their  heads,  which  can  be  removed  after  the  piles  are 
driven.  A  final  penetration  of  one  inch  under  the  last  blow  of  a 
2,000-pound  hammer  is  generally  satisfactory  and  small  enough 
to  insure  permanence. 

Several  kinds  of  concrete  piles  are  now  largely  used,  and  are 
more  permanent  and  durable  than  wood,  though  at  a  higher  cost. 
The  new  union  depot  at  Winnipeg,  Manitoba,  for  the  Canadian 
Northern  Railway  and  the  Grand  Trunk  Pacific  Railway,  con- 
tracted for  at  the  author's  estimate  of  about  a  million  dollars, 
stands  on  a  foundation  of  concrete  piles  costing  $1.25  per  lineal 
foot  in  place.  Further  particulars  of  concrete  piles  can  be  found 
in  treatises  on  concrete  or  foundations. 

ANCHOES. 

Table  XXVIII  gives  in  a  general  way  the  recommended  sizes 
of  anchor  bolts  for  several  kinds  of  columns.  It  is  intended  as  a 
general  guide  and  does  not  apply  to  special  cases  with  shear  or 
tension  on  the  anchors.  No  bolts  are  used  less  than  f  inch 
diameter,  and  the  united  area  of  the  bolts  is  about  J  the  area  of 
the  column.  As  they  are  of  small  diameter,  no  econonry  results 
from  upsetting,  which  process  should  be  used  only  on  anchor  bolts 
of  the  following  lengths  and  sizes : 

%,  %  and  1  in.  diam.  bolts  over  5  ft.  long,  use  %  in.  smaller  and  upset. 
1%,  1%  and  iy2  in.  diam.  bolts  over  5  ft.  long,  use  ^4  in.  smaller  and  upset. 
1%,  1%  and  1%  in.  diam.  bolts  over  4  ft.  long,  use  %  in.  smaller  and  upset. 
2  ,2%  and  2^4  in.  diam.  bolts  qver  4  ft.  long,  use  %  in.  smaller  and  upset. 

Set  bolts,  or  those  which  are  built  solid  with  the  masonry, 
should  be  used  for  all  towers,  trestles  and  posts  carrying  jib' 
cranes,  and  crane  girders  or  posts  subject  to  shocks  or  heavy  moving 
loads.  They  should  be  used  also  in  the  columns  of  buildings  with 
corrugated  iron  sides,  or  for  high  and  narrow  buildings,  where 
the  wind  stresses  may  nearly  or  entirely  balance  the  dead  loads. 


FOUNDATIONS  AND  ANCHORAGES 


201 


TABLE  XXVIII. 
SET    ANCHOR   BOLTS    FOE    POSTS    OF    VARIOUS    SECTIONS. 

Zee  Bar  Columns.  Area  of 

Anchor  PL 

Section.                                                    2  Bolts.  4  Bolts.  sq.  ins. 

6XV±,  Z  cote 1%  %  HO 

6X%,  Z  cols 1%  1  100 

8  X  Vi,  Z  cols 1^4  %  150 

8X%,  Z  cols 1%  1%  236 

] OX  A,  Z  cols 1%  1  180 

10Xi7i?,  Z  cols 1%  1^4  300 

Channel  Columns.  Area  of 

Anchor  PI. 

Section.                                                    2  Bolts.  4  Bolts.  sq.  ins. 

2   6-iu.   channels %  %  75 

2   7-in.   channels %  %  75 

2   8-in.   channels %  %  75 

2   9-in.   channels 1%  %  110 

2   10-in.   channels 1%  %  110 

2   12-in.  channels H4  %  150 

Angle  Columns.  Area  of 

Anchor  PI. 

2  Bolts.  4  Bolts.  sq.  ins. 

4  angles,  2X2X^5 94  %  75 

4  angles,  2  X  2  X  J4 %  %  75 

4  angles,  21/2X2Xi33 %  %  75 

4  angles,  2%  X2XV4 %  %  75 

4  angles,  3X2 X*4 %  %  75 

4  angles,  3  X  2  X  % %  %  75 

4  angles,  S1^  X  2%  X  % %  %  75 

4  angles,  3V2 X2V2 X % , 1%  %  110 

4  angles,  4X3X/e 1%  %  110 

4  angles,  4X3X% IVs  %  HO 

Four  Angle  and  Plate  Columns.  Area  of 

Anchor  PL 

Section.                                                    2  Bolts.  4  Bolts.  sq.  ins. 

4   angles,    2%  X 2 X ^4 %  %  75 

1   plate,   7X^4 

4   angles,    2V2  X2X 14 T/s  %  75 

1   plate,   8  X  % 

4   angles,   2%X2X% %  %  75 

1   plate,    10X14 

4  angles,   3  X  2  X  *4 %  %  75 

1   plate,    8X% 

4   angles,   3X2 X% 1%  %  HO 

1   plate,    10X!/4 

4   angles,   3X2 X& !Vs  %  HO 

1  plate,  ]  2  X 14 

4  angles,   3V2  X2X% 7/s  %  75 

1  plate,  8X% 

4   angles,   3%X2XU J^*  %  H° 

1  plate,  lOX1^ 

4  angles,  3i/,X2X14 1%  %  HO 

1   plate,    12X^4 

4  angles,    3% X2X Vi 1%  %  110 

1   plate,   14X1/4 


202  MILL  BUILDINGS 

Anchor  plates  should  generally  be  set  about  f  of  the  height  of 
pier  below  the  top  and  should  have  a  thickness  not  less  than  J  of 
the  bolt  diameter,  plus  -J  inch.  The  area  of  the  anchor  plate  should 
be  about  eight  times  the  value  of  the  anchor  bolts  in  tons.  Bent 
anchor  bolts  in  U  form  with  nuts  on  the  upper  stems,  require  no 
anchor  plates. 

Rough  or  foxtail  bolts  set  6  inches  in  the  cap  and  fastened 
with  cement,  should  be  used  for  all  other  anchorages. 

The  framework  of  a  large  structural  shop  in  the  East,  when 
the  erection  was  only  partially  completed,  was  struck  by  a  violent 
wind  storm  before  the  bracing  was  in  place,  and  successive  bays 
of  framing,  including  trusses  and  columns,  were  blown  over  in  one 
direction,  but  the  columns  had  been  so  firmly  anchored  by  set 
bolts  to  the  piers,  that  their  bases  remained  fastened  in  their 
original  horizontal  positions,  while  the  columns  bent  or  broke 
4  or  5  feet  above  the  bottom,  showing  the  effectiveness  of  set 
anchors  in  producing  square  action  for  columns.  The  practice  of 
the  author  in  proportioning  building  columns  is  to  consider  them 
as  square  ended  or  fixed  at  the  base,  if  they  are  firmly  anchored 
or  if  they  have  load  enough  upon  them  to  hold  them  down,  but 
smaller  columns  and  particularly  those  with  only  plug  anchors, 
frequently  have  a  tendency  to  pin  action. 

Anchor  bolts  are  located  with  wood  templets  supported  on 
stakes  above  the  piers,  the  position  of  the  holes  being  carefully 
located  on  the  templet  with  a  transit  and  level.  The  bolts  are 
suspended  through  holes  in  the  templet,  and  are  built  into  the  piers, 
Holes  for  plug  anchors  are  drilled  after  the  columns  have  been 
set,  and  they  are  fastened  to  the  masonry  with  melted  lead  or 
sulphur. 


CHAPTER  XIX. 

WALL  DETAILS. 

Walls  are  for  the  purpose  of  carrying  loads,  and  forming  an 
enclosure  to  retain  heat;  and  solid  walls  are  made  either  of  a  uni- 
form thickness,  or  with  thin  curtain  walls  and  piers  at  the  panel 
points  to  sustain  the  loads.  Framed  walls  have  wood  or  steel 
columns  and  sheet  metal  or  plank  covering.  The  common  types 
are  stone,  brick,  combined  brick  and  concrete,  concrete  blocks, 
reinforced  concrete,  sheet  metal  and  plank. 

THICKNESS  OF  WALLS. 

Sufficient  wall  thickness  must  be  provided  under  loads  to 
produce  no  greater  pressure  than  125  pounds  per  square  inch  on 
brick,  200  pounds  on  concrete,  and  250  pounds  per  square  inch 
on  stone,  and  concentrated  loads  must  be  distributed  over  the 
wall  with  stone  or  iron  bearing  blocks. 

If  solid  masonry  piers  would  be  excessively  large  or  take  more 
space  than  is  available,  steel  columns  may  be  inserted  in  the  piers, 
with  only  enough  covering  around  them  to  serve  as  fireproofing. 
The  method  of  using  steel  columns  to  carry  all  the  loads  is  waste- 
ful, because  the  compression  value  of  the  material  around  the 
column  is  not  considered.  A  more  economical  method  is  that  used 
for  reinforced  concrete  columns,  in  which  light  steel  is  inserted 
large  enough  to  support  the  dead  load,  and  when  completed,  the 
whole  area  of  both  steel  and  concrete  are  available  in  compression. 
Broad  and  shallow  pilasters  are  preferable  to  narrow  and  deeper 
ones,  as  they  have  a  stronger  appearance. 

STONE  WALLS. 

Stone  walls  are  not  as  much  used  for  factory  buildings  as  for- 
merly, excepting  in  districts  where  stone  is  accessible  and  cheap, 
and  other  material  higher  in  price.  A  notable  set  of  large  new 
buildings  with  walls  entirely  of  stone  are  those  for  the  Associated 
Industries  at  Sault  Ste.  Marie,  Ontario.  The  stone  is  a  spotted 
pink  granite,  quarried  on  the  site  or  in  the  immediate  vicinity, 
and  presents  an  unusually  attractive  appearance.  Stone  walls  12 
to  18  inches  thick,  cost  50  to  70  cents  per  square  foot. 

203 


204 


MILL  BUILDINGS 


BRICK  WALLS. 


Solid  brick  walls  without  columns  are  rigid  and  free  from  the 
vibrations  common  in  mill  buildings  with  framed  walls.  Brick 
walls  with  piers  and  thin  curtains  between,  are  less  rigid  but  much 
used.  The  required  thickness  of  walls,  according  to  the  building 
laws  of  several  cities,  is  given  in  Chapter  V.  Brick  walls  absorb 
water  and  are  free  from  condensation  inside,  but  if  moisture  must 
be  excluded,  paving  bricks  may  be  used  on  the  exterior  and  enam- 
eled brick  on  the  interior,  as  in  the  new  shops  of  the  American 
Arithmometer  Company. 


Fig.   346. 


SIZE  AND  COST  OF  BRICK. 

The  standard  size  adopted  by  several  brick  manufacturers  is 
for  common  brick,  2J  X  4  X  8J,  and  for  face  brick  2J  X  4J  X  8§ 
inches,  and  in  the  walls,  including  mortar  joints,  they  usually  lay 
22%  bricks  per  cubic  foot,  or  7J  per  square  foot  of  wall  surface  for 
each  4  inches  in  thickness.  One  thousand  new  bricks  piled  close 
occupy  58  cubic  feet,  while  the  same  number  of  old  cleaned  bricks 
measures  70  cubic  feet. 

Hard  bricks  when  struck  together  emit  a  clear  ring,  and  good 
ordinary  brick  should  absorb  not  over  10%  of  their  weight  of  water, 
and  the  best  not  over  5%,  while  soft  bricks  will  take  up  25  to  35% 
of  their  weight. 

Per  M. 

Common  brick  costs $  6  to  $10 

Paving  brick  costs 14  to     1(5 

Glazed  brick  costs 20  to     25 

Face  brick  costs 25  to     30 

Moulded  brick  costs 40  to     50 

Enameled  brick  costs . .  70  to     80 


WALL  DETAILS 


MORTAR. 


205 


Lime  weighs  66  pounds  per  bushel,  53  pounds  per  cabic  foot, 
and  230  pounds  per  barrel,  and  costs  40  cents  per  bushel.  (1909.) 

Portland  cement  weighs  from  90  to  100  pounds  per  cubic  foot, 
and  a  barrel  weighs  375  pounds  and  costs  about  $1.35  at  Chicago, 
while  Rosendale  or  natural  cement  weighs  50  to  60  pounds  per 
cubic  foot  and  a  barrel  weighs  300  pounds  and  costs  80  cents 
to  $1.00. 

Seashore  sand  is  not  suitable  for  making  mortar,  for  the  salt 
which  it  contains  forms  efflorescence  on  the  brickwork,  and  good 
sand  ordinarily  costs  from  75  cents  to  $1.25  per  cubic  yard. 


SIDE:  ELEVATIOH. 

Fig.  347. 

One  barrel  of  unslacked  lime  will  make  2^  barrels  of  stiff  lime 
mortar  paste,  or  6J  barrels  of  mortar  of  one  to  three  proportion. 

The  amount  of  mortar  required  to  lay  1,000  bricks  is  as 
follows : 

Lime  mortar,  2%  bus.  of  lime  and  %  cu.  yd.  of  sand. 

Lime  and  cement  mortar,  2  bus.  of  lime,  1  bbl.  cement,  %  cu.  yd.  of  sand. 

Cement  mortar  (1-3),  l1/^  bbls.  cement  and  %  cu.  yd.  of  sand. 

In  making  mortar  the  lime  and  cement  should  be  thoroughly 
mixed  before  water  is  added,  and  the  mortar  must  be  made  only  in 
small  quantities  as  needed. 

COST  OF  BRICKWORK. 

The  cost  of  brickwork  depends  largely  upon  the  rate  at  which 
the  bricks  are  laid.  A  man  and  helper  can  lay  1,300  common 


206 


MILL  BUILDINGS 


brick  per  day  of  8  hours  on  ordinary  straight  walls,  or  1,000  to 
1,200  on  walls  that  are  more  broken,  while  in  the  same  time  one 
man  with  half  the  time  of  one  helper  will  lay  only  400  to  600  face 
bricks.  Enameled  brick  around  piers  and  openings  are  laid  at  the 
rarte  of  100  to  300  per  man  per  day,  depending  on  facilities  and 
conditions. 

One  helper  is  required  for  each  bricklaj^er  on  solid  walls,  and 
one  helper  for  every  two  men  laying  9-inch  walls  with  pressed 
brick  face.  Ordinary  hods  contain  18  bricks. 

A  table  of  wages  paid  to  bricklayers  and  laborers  in  different 
parts  of  North  America  is  given  in  Chapter  XLI.  The  cost  of 
laying  common  brick  varies  considerably  but  is  generally  about 


Fig.  348. 

$6.00  per  M,  and  face  brick  $10.00  per  M.    Itemized  costs  of  com- 
mon and  face  brick  in  walls  are  as  follows : 

Cost  of  common  brick  per  M  laid  at  the  rate  of  1,000  brick  per 
man  per  day — 

PerM. 

Brick  costs $  7.00 

Sand,  %  yard 75 

Cement,  1%  bbls.  at  $1.35 2.00 


Material    $  9.75 


PerM. 

Hauling $  1.00 

Hoisting    50 

Mason,  8  hours 5.00 

Helper,  8  hours 2.50 


Total   $18.75 


Cost  of  face  brick  per  M,  laid  at  the  rate  of  500  per  man  per 
day — 

Per  M.  Per  M. 

Brick   costs $25.00      Hauling $  1.00 

Sand,  %  yard 75       Hoisting    50 

Cement,  1%  yards  at  $1.25.  . .     2.00       Mason,  16  hours.  . ./ 10.00 

Helper,  8  hours 2.50 


Material    .  ..$27.75 


Total   .  ..$41.75 


The  cost  of  12-inch  common  brick  walls  at  $20.00  per  M  for 
brick  in  place  is  as  follows : 


WALL  DETAILS  207 

Twenty-two  and  one-half  bricks  at  2  cents  each  is  45  cents  per 
square  foot,  while  the  average  cost  per  square  foot  for  an  8-inch 
brick  curtain  wall  with  enclosed  steel  columns  is : 

Per  sq.  ft. 
(cents.) 

Steel,  4  Ibs.,  at  4  cents 16 

Brick,  15  Ibs.,  at  2  cents 30 

Total  cost  per  sq.  ft ; 46 

COMBINATION  BEICK  AND  CONCRETE  WALLS. 

A  type  of  wall  construction  for  mills  and  factories  which  has 
more  merit  than  almost  any  other,  has  the  columns,  foundations, 
sills  and  lintel  beams  made  of  reinforced  concrete,  with  a  light 
filling  wall  between.     The  reinforced  concrete  columns  (Fig.  349) 
have  angle  irons  heavy  enough  to  support  the 
trusses  during  erection  and  have  side  grooves  to 
receive  the  filling  wall,  which  may  be  either 
brick  or  concrete,  brick  being  the  cheaper.   The 
construction    permits    the    use    of    steel    roof 


Fig.  349.  trusses  and  girders,  which  can  be  fitted  to  the 

column  angles  before  the  concrete  has  been 
placed,  insuring  good  connections.  Buildings  of  this  kind  are 
erected  rapidly,  for  the  whole  framing  can  be  placed  without  wait- 
ing to  complete  the  wall. 

A  very  neat  and  artistic  effect  is  obtained  by  covering  the  wall, 
both  piers  and  curtain  panels,  with  4  inches  of  buff  or  yellow  face 
brick.  The  average  cost  per  square  foot  for  such  a  wall  without 
the  brick  covering  and  columns  20  feet  apart  is  as  follows : 

Per  lin.  / 1. 
of  col. 

Column  concrete,  2  cu.  ft.,  at  25  cents $0.50 

Column  steel,   10  pounds,   at  4  cents 40 

Column  forms 50 

Total  cost  per  lin.  ft.  of  col $1.40 

Per  sq.  ft. 
of  wait. 
OR 

Cost  of  col.  and  pilaster $0.07 

8-inch  brick  curtain  wall,  15  bricks,  at  2  cents 30 

Total  average  cost  per  square  foot  of  wall $0.37 

REINFORCED  CONCRETE  WALLS. 

A  light  strong  reinforced  concrete  wall  (Fig.  350)  is  made  by 
placing  a  light  double  angle  iron  frame  in  the  panels  between  the 


208 


MILL  BUILDINGS 


columns,  heavy  enough  to  support  the  windows  and  braced  at  the 
corners  with  thin  plates.  After  the  frame  is  erected,  concrete  is 
run  in  between  plank  forms,  and  the  steel  frame  is  afterwards 
painted  red  or  black  in  contrast  to  the  concrete.  This  kind  of 
wall  costs  more  than  some  others,  owing  to  the  presence  of  the 
permanent  angle  iron  frame  and  the  need  of  forms;  but  when 
brick  is  expensive  and  sand  and  gravel  convenient,  it  may  be 
economical.  It  can  be  erected  in  units,  and  single  panels  can  be 
removed  more  easily  than  monolithic  walls. 

The   objection    to   solid    concrete    walls    is   that    condensation 
forms  on  the  inside  in  cold  weather  and  discolors  the  wall  and 


2<  2*2  *3i6\\  Latticed 


c/o 


do,  I 


Fig.  350. 

adjoining  floor.     An  average  square  foot  cost  of  an  8-inch  con- 
crete wall  as  described  above  is: 

Per  sq.  ft. 
(cents.) 

Steel  frame,  4  Ibs.,  at  4  cents  per  Ib 16 

Concrete,  8  ins 20 

Forms,  2  sides 10 

Total    .  46 


Walls  of  concrete  and  expanded  metal  are  used  in  several 
buildings  designed  by  the  author,  illustrated  in  Figs.  24,  25,  26, 
51  and  52.  The  framing  consists  of  f-inch  channels  placed  verti- 
cally 12  to  16  inches  apart,  and  fastened  to  longitudinal  steel  girths 
attached  to  the  columns.  The  light  channels  are  covered  with 
expanded  metal,  which  supports  a  2-inch  concrete  wall. 


WALL  DETAILS  209 

These  walls  require  the  use  of  forms  on  both  sides  for  placing 
the  concrete  and  the  cost  per  square  foot  of  2-inch  concrete  and 
expanded  metal  wall  is  as  follows: 

Per  sq.  ft. 
(cents.) 

2  in.  concrete,  at  2%  cents  per  sq.  f t 5 

Expanded  metal 2 

Forms,  2  sides 10 

Steel,  4  Ibs.,  at  4  cents 16 

Total  cost  per  sq.  ft 33 


The  shop  office  (Fig.  41)  and  the  market  building  (Fig.  32) 
designed  by  the  author  have  double  concrete  walls  with  air  space 
between  them.  The  outer  2-inch  slab  is  first  formed  as  described 
above,  and  the  inner  lining  of  light  channels  and  expanded  metal 
is  then  applied  over  the  girths  and  plastered.  As  the  outer  and 
inner  girths  are  fastened  to  the  column  faces,  the  width  of  air 
space  between  the  double  wall  is  equal  to  the  column  thickness. 
The  method  is  appropriate  in  very  cold  or  very  hot  climates  where 
non-conducting  walls  are  desired.  The  cost  of  double  walls  is 
not  quite  twice  the  cost  of  single  ones  because  less  forms  are 
needed.  These  walls  are  occasionally  plastered  with  two  or  three 
coats,  the  first  coat  consisting  of  1  part  of  cement,  2  of  lime, 
and  3  of  sand,  and  later  coats  having  1  part  of  cement  and  2  of 
sand.  The  inside  is  sometimes  coated  with  gypsum  plaster  instead 
of  cement  mortar. 

Concrete  "walls  are  also  made  by  erecting  separately  molded 
slabs  3  or  4  inches  thick,  and  4  or  5  feet  square  and  hooking  them 
with  countersunk  bolts  to  the  wall  girths  (Fig.  351).  These  slabs 
are  reinforced  with  wire  fabric  or  expanded  metal,  and  are  molded 
one  upon  another  with  sheets  of  oiled  paper  between  them,  to 
prevent  the  blocks  from  adhering  while  the  concrete  is  green.  The 
government  coal  storage  pockets  at  Bradford,  Rhode  Island,  have 
corrugated  iron  walls  lined  with  concrete  slabs  as  described  above. 
The  duplicate  buildings  are  725  feet  long  and  87 -J  feet  wide,  hold 
40,000  tons  of  coal,  and  contain  more  than  4,000  of  these  concrete 
slabs. 

Molded  concrete  slabs  may  also  be  made  with  a  frame  of  2x£- 
inch  flat  bars  on  edge,  connected  with  J-inch  round  rods  4  inches 
apart,  passing  through  punched  holes  in  frame.  The  metal  rein- 
forcing is  completed  by  weaving  No.  14  wire  under  and  over  the 
rods,  6  inches  apart,  and  the  frame  is  then  filled  with  stone  con- 
crete mixed  in  1-2-4  proportion.  The  edges  are  offset  to  fit  together 


210 


MILL  BUILDINGS 


and  fasten  over  the  framework,  and  grooves  which  are  afterwards 
filled  with  cement,  are  left  in  the  slabs  for  anchor  bands. 

The  finished  slab  is  2  inches  thick,  and  is  suitable  for  sizes  up 
to  4  X  15  feet.  They  can  be  used  both  for  walls  and  roofs,  and 
lower  side  only  and  is  patented  by  The  Aiken  Cement  House 
Company. 

Concrete  walls  are  also  made  by  molding  complete  wall  sections 
in  a  horizontal  position  on  the  ground,  and  then  hoisting  them  into 
place.  The  method  has  the 
advantage  of  requiring  forms 
on  the  lower  side  only  and  is 
used  by  The  Aiken  Cement 
House  Company  of  Chicago. 

CONCRETE  BLOCK  WALLS. 

Concrete  block  walls  are 
made  of  either  single  or  double 
blocks,  the  former  going 
through  the  wall,  while .  the 
latter  are  facings  only,  an- 
chored in  with  one  or  more 
ribs.  They  are  less  expensive 
than  brick  or  stone  and  form 
not  only  a  lighter  wall  than 
either,  but  one  which  is  a  non- 
conductor of  heat  and  cold  be- 
cause of  the  hollow  center. 


Concrete  Block 


Fig.    351. 


WALL  DETAILS 


211 


Condensation  on  the  inner  face,  which  is  liable  on  walls  of 
solid  stone  or  concrete,  is  almost  or  entirely  absent  on  a  wall 
of  hollow  blocks.  Some  concrete  blocks  have  double  lines  of 


-2'^  Concrete 
Exp.  Metal 


Fig.  353. 


j f    Column 

Fig.  352. 


cores  alternating  with  each  other,  and  cross  ribs  never  extend 
through  the  wall  to  conduct  heat  or  cold  and  cause  condensation. 
The  hollow  wall  is  cheaper  than  a  solid  one  because  it  contains 
less  material,  and  it  is  also  lighter,  requiring  a  less  expensive 
foundation  to  sustain  it.  Blocks  are  made  in  much  larger  sizes 
than  brick,  and  the  cost  of  laying  them  is  proportionately  less. 
The  hollow  spaces  in  the  walls  are  convenient  for  pipes  and  there 
is  no  delay  in  waiting  for  stone  or  brick,  as  the  concrete  blocks  can 
be  made  at  the  site  by  the  men  who  erect  the  building.  The  cost 
of  the  best  concrete  block  machine  does  not  exceed  $100.  Cinder 
concrete  is  serviceable  for  interior  partitions,  but  it  is  too  porous 
to  use  in  blocks  for  outer  walls.  Another  saving  from  the  use  of 
hollow  concrete  blocks  in  preference  to  brick  or  stone,  is  that 
furring  and  lathing  on  the  inside  is  unnecessary,  as  they  contain  an 
interior  air  space,  and  plaster  can  be  applied  directly  to  the  blocks. 
Blocks  are  usually  made  from  a  mixture  of  1  part  of  cement 
with  6  or  8  parts  of  sand  and  gravel  or  crushed  stone  not  exceed- 


212 


MILL  BUILDINGS 


ing  |  inch  in  diameter,  and  faced  with  J  to  J  inch  of  fine  mate- 
rial, which  gives  a  better  appearance  and  a  more  impervious  sur- 
face. Different  kinds  of  blocks  are  made  in  the  same  molds  by 
using  different  cores.  After  being  molded,  the  blocks  require  about 
a  week  to  thoroughly  harden,  and  during  this  time  they  should 
be  occasionally  sprinkled.  They  can  be  made  at  the  rate  of  300 
square  feet  per  man  per  day,  and  single  blocks  such  as  those  in 
Figs.  353,  354  and  355,  cost  10  cents  per  square  foot,  or  25  cents 
per  cubic  foot  in  the  wall.  Walls  like  Fig.  354,  10  inches  thick, 
cost  20  cents  per  square  foot,  which  is  less  than  half  the  cost  of 
brick  walls  with  pressed  brick  face. 


Fig.  355. 


Fig.  356. 


Hollow  monolithic  walls  are  made  by  placing  concrete  between 
wooden  forms  similar  to  the  methods  used  for  solid  walls,  except- 
ing that  concrete  is  placed  around  movable  wooden  cores  3  to  4 
feet  long,  with  concrete  cross  ribs  between  them  to  unite  the  inner 
and  outer  faces. 

SHEET  METAL  WALLS. 

Corrugated  iron  is  one  of  the  most  common  and  cheapest  walls 
for  mill  buildings,  and  its  use  is  described  in  Chapter  XXV.  It  is 
suitable  only  where  interior  heating  is  unnecessary,  and  usually 
has  short  duration  owing  to  the  formation  of  rust,  but  it  is  easily 
renewed.  It  is  fastened  to  wood  or  steel  purlins,  supported  on 
the  columns,  and  when  well  braced  this  type  of  wall  is  suitable  for 
buildings  with  heavy  cranes.  Bracing  should  preferably  be  stiff, 
and  capable  of  resisting  both  tension  and  compression,  but  if  rods 


WALL  DETAILS  213 

are  used,  they  must  have  turnbuckles  or  other  adjustments  for 
tightening  them.  Corrugated  iron  walls  lined  with  concrete  are 
shown  on  page  210.  These  walls  are  also  made  double  thickness, 
thickness,  using  2|-inch  corrugations  on  the  outside  and  IJ-inch 
on  the  inside,  but  the  inside  corrugated  iron  must  be  nailed  to 
wood  strips  or  purlins,  for  the  rear  side  of  inner  sheets  are  not 
accessible  for  clinching  nails.  Fig.  21  is  a  foundry  designed  by 
the  writer,  with  side  and  rear  walls  of  corrugated  iron  and  con- 
tinuous sash. 

WOOD  WALLS. 

Wood  shop  walls  are  made  either  fixed  or  as  a  series  of  movable 
panels  or  doors,  permitting  all  or  half  of  the  sides  to  be  opened 
when  desired. 

Permanent  wood  walls  are  generally  made  of  plank  standing 
vertically,  spiked  to  horizontal  purlins,  with  joints  between  planks 
covered  with  J-inch  battens,  or  of  matched  sheathing  without 
battens  (Fig.  357).  If  instead  of  battening  the  joints  the  wall  is 
covered  with  corrugated  iron  or  metal  siding,  the  plank  should 
then  be  horizontal,  and  fastened  to  columns  and  intermediate 
studs.  Plank  walls  shown  in  Fig.  368  are  weather-proofed  with 
slate.  Wood  walls  made  of  movable  panels  are  most  convenient 
when  arranged  to  roll  horizontally  past  each  other,  leaving  one- 
half  of  the  side  area  open  (Fig.  16).  The  whole  wall  space  may 
be  opened  by  using  continuous  counterweighted,  sliding,  rolling 
or  folding  doors,  at  an  increased  cost. 

The  detail  cost  of  a  weather-boarded  plank  wall  is  as  follows : 

Per  sq.  ft. 
Cents. 

Steel  framework,  4  Ibs.,  at  4  cents 16 

2-in.  plank,  at  3  cents 6 

Sheathing  paper % 

Weather  boarding .  . .  .* 6 

Paint,   2   coats 2 

Total  cost  per  sq.  ft 30% 

WALL  ANCHORAGES. 

Fig.  369*  is  a  common  truss  and  wall  connection  with  two 
f-inch  bolts  passing  through  the  bottom  truss  angles,  fastened  to 
a  projecting  steel  plate  built  into  the  masonry.  Bolts  are  easily 
inserted  and  the  anchorage  is  usually  satisfactory,  permitting  a 
slight  variation  in  the  distance  between  walls,  without  affecting 
the  connection. 


Mill  Building  Construction,  H.  G.   Tyrrell,  1900. 


214 


MILL  BUILDINGS 


,00 


Flashing 


^ 


^7/d  Matched  Cheating 

Fig.   357. 

Anchors  like  Fig.  370*  are  more  secure  but 
require  greater  care  in  setting  the  wall  bolts, 
and  must  have  slotted  anchor  holes  in  the  shoe 
plates.  Bolts  and  anchor  plates  are  built  into 
the  walls,  and  the  trusses  placed' afterwards. 
The  trusses  in  Fig.  371  rest  on  stone  seats,  and 
after  they  are  placed,  holes  are  drilled  in  the 
stones,  and  plug  bolts  set  with  lead  or  sulphur. 
In  Fig.  372  the  trusses  are  built  into  the  wall 
and  held  by  angle  clips  at  the  end. 

Fig.  373  is  a  method  of  attaching  a  new 
steel  truss  to  the  inside  of  an  old  wall  without 
cutting  it.  Bolt  holes  are  drilled  through  the 
wall  to  match  those  in  the  outside  washer  plate, 
the  area  of  which  in  square  inches  must  be 
equal  to  eight  times  the  tension  on  the  bolts  in 
tons.  The  bearing  value  in  tons  for  bolts  of 
different  sizes  in  walls  of  various  thicknesses, 
and  the  required  area  of  washer  plates  for  each 
bolt  is  given  in  the  following  table: 


Fig.  358. 


Diameter 
in  ins. 


TABLE  XXIX.* 


8-in.  Wall. 


12-in.  Wall. 

.7 

.9 

1.05 
1.2 


16-in.  Wall. 

1.6 

1.4 
1.6 


Area 
of  pi. 

%04n.  Wall.  sq.  ins. 
18 
26 


1.77 


46 


WALL  DETAILS 


215 


Fig.  369. 

s- 2 Rough  Bolts 

»    ^e/  in  Cement 


Fig.   371. 


Fig.  370. 


Fig.  372. 


The  trusses  must  be  carefully  set,  using  filler  plates  if  neces- 
sary, between  the  truss  and  wall.  When  bolts  cannot  be  passed 
through  the  wall,  trusses  are  then  fastened  with  expansion  bolts, 
the  bearing  value  of  which,  for  different  lengths  and  sizes,  are  as 
follows : 


Fig.  373. 


Fig.  374. 


Fig.   375. 


Fig.   376. 


216 


Diameter 
in  ins. 


MILL  BUILDINGS 
TABLE  XXX.* 


ins. 


6  ins. 

long. 
.36 
.42 
.47 
.57 


8  ins. 

long. 
.46 
.56 
.65 
.75 


10  ins. 
long. 
.52 
.70 
.81 
.93 


12  ins. 


.84 

.99 

1.12 


S  ect  ion  /  Slag  Hoofing. 

through  Roof.  J  /  l^"  Sheathing . 


Elevation    of  Joint;     Main  Building. 


4'*4' Hemlock 
-Ma in  Column. 


"•-*••*'-•"""*•  M-^-**-*       '^ry^***f^*^**M^*f*TJ 

Plan  through  Pilasters 
Expansion  Joint  in  Main  Shop  Walls  and  Roof., 

Fig.  377. 

Fig.  374  is  the  anchorage  for  a  beam  in  brickwork,  the  length 
of  anchor  being  6  inches  greater  than  the  width  of  beam  flange. 

Fig.  375  shows  a  lattice  strut  anchored  to  the  wall  with  bolts 
3  or  4  feet  apart.  When  walls  are  already  built,  bolts  must  extend 
through  the  wall  with  washer  plates,  or  the  strut  may  be  fastened 
with  expansion  bolts.  The  ends  of  angle  struts  are  fastened  into 
brickwork,  as  shown  in  Fig.  376.  A  round  rod  forged  out  flat  at 
one  end,  is  threaded  and  fitted  with  double  nuts  and  cast  wash- 
ers, the  flattened  part  being  punched  for  connection  to  the  angle 


WALL  DETAILS 


217 


strut.  Two  holes  and  a  J-inch  rod  are  required  for  a  2-inch 
angle  strut,  three  holes  and  a  1-inch  rod  for  2J-inch  angles,  and 
four  holes  with  a  1^-inch  rod  for  3  angle  struts.  The  length 
between  washers  must  be  made  to  suit  the  wall  thickness. 


*&Galv.Steei  Flashmy 
Crimped 


•+&&*+ 

*•        ^w^*}//)xg0//////A£^!\     |e  J 


inupus  Spring  Piece. 


Galv.  Corrucf.  Steel.-? 


CHAPTER  XX. 

GROUND  FLOORS. 

Shop  floors  are  of  two  general  kinds:  (1)  Ground  Floors,  or 
those  which  rest  upon  the  soil,  (2)  Upper  Floors,  supported  on  a 
frame  of  beams  and  columns,  the  construction  of  these  two  kinds 
being  quite  different.  The  purpose  of  the  building  and  its  contents 
will  determine  the  most  suitable  kind  of  floor  in  each  individual 
case.  Some  shops  containing  only  very  heavy  machinery,  require 
special  foundations  for  each  machine,  but  other  shops  for  light 
work  are  more  convenient  when  built  with  a  solid  floor  on  which 
machines  can  be  placed  anywhere  without  special  foundations. 

Ground  floors  may  be  made  of  natural  compacted  earth  or 
clay,  cement  or  tar  concrete,  brick,  asphalt,  plank,  or  wood  blocks. 
Permanent  or  solid  floors  should  be  built  like  a  street  pavement, 
with  a  finished  wearing  surface  bedded  on  substantial  founda- 
tions, and  should  have  a  grade  of  about  1  or  2  inches  per  100  feet 
for  drainage.  Certain  other  buildings,  such  as  car  shops,  round- 
houses, etc.,  in  which  water  is  freely  used  for  washing,  should 
have  a  greater  floor  slope  to  drain  them  quickly,  for  men  cannot 
do  effective  work  when  standing  in  wrater.  The  ground  floors  of 
steel  frame  buildings  which  are  usually  made  and  erected  by 
structural  companies,  can  be  laid  more  cheaply  by  the  owner  or  a 
local  builder,  and  ground  floors  should  therefore  not  be  included 
with  a  structural  contract. 

KIND  OF  FLOORS. 

Experience  has  proven  that  different  types  of  floors  are  best 
suited  for  different  kinds  of  manufacturing  buildings.  Clay  or 
earth  are  the  best  suited  for  forge  shops  or  foundries  where  the 
presence  of  hot  metal  makes  wrood  flooring  prohibitive.  A  floor 
made  by  laying  vitrified  brick  on  plank  foundation,  water-proofed 
on  the  underside  and  imbedded  in  sand,  is  largely  used  and  is 
satisfactory  for  foundries. 

Machine  shops  or  other  buildings  where  men  stand  continu- 
ously, should  have  floors  with  a  wearing  surface  of  wood  or  asphalt, 
for  cement,  stone  or  brick  are  too  cold  and  unresisting  and 

218 


GEOUND  FLOOES  219 

tire  the  workmen.  Asphalt  is  more  comfortable  to  walk  upon  than 
wood,  but  is  not  as  well  suited  for  machine  shops,  because  oil 
softens  asphalt,  and  wood  floors  are  therefore  best,  wherever  oil  is 
liable  to  drip.  Floors  of  machine  shops  should  be  smooth  and 
clean,  so  dust  will  not  rise  and  settle  on  the  machinery;  earth  or 
macadam  are  therefore  unsuitable.  They  should  be  firm  enough  to 
support  small  machines  anywhere,  and  are  sometimes  made  to 
carry  even  heavy  machines  at  any  place  without  special  founda- 
tions. These  floors  receive  hard  usage,  not  only  from  the  direct 
weight  placed  upon  them,  but  also  from  having  castings  dragged 
along  the  floor  by  the  cranes,  and  they  must  be  strong  enough  to 
stand  the  service. 

The  railroad  companies  have  experimented  with  many  kinds  of 
floors  in  roundhouses,  and  have  accepted  brick  pavement  as  the 
best.  Cement  or  granolithic  surfaces  are  found  to  break  and 
crumble  from  the  action  of  heavy  hydraulic  jacks  and  the  weight 
of  trucks  and  driving  wheels.  Timber,  cedar  block  and  cinder 
floors  have  all  been  found  inadequate  for  the  same  reasons,  and 
while  brick  paving  is  often  damaged,  it  can  easily  be  repaired  by 
taking  up  part  of  the  floor  and  replacing  it  without  disturbing 
the  rest. 

CEMENT  CONCRETE  FLOORS. 

Concrete  floors  with  cement  mortar  surface  are  laid  like  base- 
ment floors  on  a  foundation  of  broken  stone,  cinders  or  gravel. 
The  sand,  gravel  and  stone  should  be  clean  and  free  from  foreign 
matter  such  as  clay  or  loam,  and  the  method  of  mixing  and  placing 
the  concrete  should  be  similar  to  that  used  in  other  kinds  of 
concrete  construction.  A  convenient  method  of  determining  the 
proportions  of  material  to  use,  is  to  fill  a  barrel  with  sand  and  find 
the  amount  of  water  that  can  be  poured  in  without  overflowing; 
the  water  represents  the  quantity  of  cement  that  must  be  used 
with  a  barrel  of  sand.  If  gravel  and  broken  stone  are  used,  an- 
other barrel  should  be  filled  with  gravel,  and  water  poured  in  as 
before,  to  determine  the  amount  of  mortar,  or  cement  and  sand 
needed  for  a  barrel  of  gravel.  Another  barrel  may  be  filled  with 
broken  stone,  and  the  amount  of  water  that  it  will  hold  represents 
the  quantity  of  cement,  sand  and  gravel  to  be  added  to  the  stone. 
In  order  to  have  the  sand,  gravel  and  stone  thoroughly  covered 
with  cement,  the  proportion  of  finer  material  should  be  slightly 
greater  than  indicated  by  the  above  tests,  exceeding  the  water 


22Q  MILL  BUILDINGS 

volumes  by  about  10%.  A  barrel  of  cement  contains  four  bags 
measuring  3.8  cubic  feet  and  weighs  380  pounds.  The  thickness 
of  foundation  depends  on  the 
nature  of  the  soil  and  on  the 
load  the  floor  must  sustain. 
Where  ground  is  compact  and 
firm,  a  single  4  or  5-inch  layer 
of  concrete  may  be  enough, 
but  softer  soils  may  need  a 
thicker  floor  made  of  several 
layers  of  broken  stone,  gravel, 

or  sand  under  the  concrete.  Soft  or  spongy  places  should 
be  dug  out  and  refilled  with  solid  material.  Figure  379  is  a 
section  of  a  concrete  floor  having  a  6-inch  broken  stone  foun- 
dation overlaid  with  8  inches  of  concrete  and  covered  with  a  4-inch 
thickness  of  spruce,  under  yellow  pine  or  maple.  The  soil  should  be 
excavated  to  a  depth  of  18  inches  and  the  surface  well  rammed 
before  placing  the  broken  stone.  A  wearing  surface  containing 
asphalt  in  combination  with  cement  mortar  is  more  elastic  than 
solid  cement  finish,  and  is  sometimes  preferred.  Another  floor 
shown  in  Fig.  380  has  several  layers,  the  thickness  of  which  de- 
pends upon  local  requirements.  On  a  well  rammed  subsoil,  is 
laid  8  to  12  inches  of  broken  stone,  which  is  covered  with  4  to  6 
inches  of  smaller  crushed  stone,  each  layer  being  thoroughly 
rammed  before  placing  the  next  one.  Concrete  is  then  spread 
2  to  4  inches  thick  and  covered  with  -|  inch  to  1  inch  cement 
mortar  surface.  The  top  dressing  is  made  by  mixing  one  part  of 
cement  with  one  to  one  and  one-half  parts  of  sand,  while  a  good 
proportion  for  concrete  is  one  part  of  cement  mixed  with  two  of 
sand  and  five  of  gravel  and  broken  stone.  The  concrete  below  the 
upper  dressing  must  be  carefully  rolled  and  leveled  before  applying 
the  wearing  surface,  and  the  dressing  should  be  placed  before  the 
concrete  has  had  time  to  harden,  so  it  will  adhere  to  its  foundation. 
If  the  concrete  stands  long  enough  to  become  thoroughly  hard  on 
the  top,  the  mortar  surface  is  liable  to  crack  and  crumble.  The 
surfacing  must  be  laid  in  blocks  4  to  5  feet  square,  with  joints 
between  them,  so  if  cracks  should  develop  from  change  of  tem- 
perature or  contraction  of  the  material,  they  will  follow  the  joints 
and  prevent  irregular  breaks  from  disfiguring  it.  The  surfacing 
must  be  protected  for  one  or  two  days,  to  give  the  cement  time  to 
harden  before  being  thrown  open  to  travel.  A  floor  of  this  kind 
was  laid  in  the  machine  shop  at  the  Brooklyn  Navy  Yard,  the  top 


GBOUND  FLOOES 


221 


dressing  being  colored  brownish  red  for  better  appearance. 

A  method  of  fastening  light  machines  to  the  floor  is  shown 
in  Fig.  381.    Troughs  made  of  sheet  metal,,  with  angle  iron  edge, 


'/2  "to  i'SurfacB  3  "Concrete  •-. 


•4"-6  "Crushed   '-tf-^Dro 
Stono  Stone 


Fig.  380. 


Fig.  381. 


are  built  into  the  cement,  and  flat-head  bolts  are  inserted  into  the 
grooves  and  turned  sideways. 

The  cost  of  concrete  floors  varies  with  the  richness  of  concrete 
and  its  thickness,  and  may  be  found  for  any  particular  case  from 
the  following  unit  prices: 

Portland  cement,  per  bbl.,  costs  from $1.50  to  $2.00 

Sand  and  gravel,  per  cu.  yd.,  costs  from 1.00  to  1.50 

Crushed  limestone,  per  cu.  yd.,  costs  from 1.50  to  1.75 

Concrete  in  place,  per  cu.  ft.,  costs  from 20  to  .25 

A  6-inch  layer  of  concrete  costs  from  10  to  12  cents  per  square 
foot,  and  for  each  additional  inch  of  concrete  is  added  2  cents 
per  square  foot,  or  18  cents  per  square  yard.  One  inch  cement 
mortar  surfacing  costs  6  cents  per  square  foot. 

A  light  cement  floor  composed  of  J-inch  mortar  surface  on 
a  2-inch  layer  of  concrete  is  reported  to  have  cost  66  cents  per 
square  yard,  itemized  as  follows: 


Sand,  gravel  and  stone,  per  sq.  yd.,  costs $0.10 

Cement,  per  sq.  yd.,  costs 30 

Labor,  per  sq.  yd.,  costs 26 

One  barrel  of  cement  was  enough  to  lay  100  square  feet  of 
the  above  floor,  2J  inches  thick.  A  similar  floor  with  J-inch 
wearing  surface  on  5-inch  concrete  costs  from  $1.00  to  $1.25  per 
square  yard.  Labor  for  surface  dressing  costs  15  cents  a  square 
yard,  while  the  labor  cost  of  forming  side  floor  gutters  is  15  to 


222  MILL  BUILDINGS 

20  cents  per  lineal  foot.  Cement  wall  base  10  inches  high  and 
f  inch  thick  costs  12  to  20  cents  per  lineal  foot,  the  former  price 
being  for  large  quantities.  Five  laborers  and  one  finisher  can 
lay  600  square  feet  of  concrete  floor  6  inches  thick  in  8  hours. 
The  wages  paid  to  cement  finishers  and  laborers  in  different  parts 
of  the  United  States  and  Canada  are  given  in  the  table  on  page 
420.  Labor  costs  from  20  to  60  per  cent  of  the  cost  of  mate- 
rials, depending  on  the  thickness  of  floor  and  the  rate  of  wages 
paid. 

TAR  CONCRETE  FLOORS. 

A  foundation  of  coal  tar  or  asphalt  concrete  is  the  best  pre- 
servative for  wood,  for  when  laid  over  cement  concrete  without 
any  protective  coating,  wood  plank  and  sleepers  decay  rapidly 
from  dry  rot.  Several  methods  of  preserving  floor  lumber  have 
been  tried,  especially  the  plan  of  spreading  lime  under  it, 
but  no  preservative  is  so  effectual  as  tar  or  pitch,  or  a  combination 
of  the  two  materials.  A  concrete  floor  overlaid  with  plank  is  the 
best  for  machine  shop  use;  it  is  solid,  without  vibration,  is  com- 
fortable to  walk  upon,  and  machines  can  be  screwed  to  any  part 
of  the  floor.  As  there  is  no  air  space  beneath  it,  .the  floor  is 
practically  fireproof,  is  not  expensive,  and  tools  falling  upon  it 
do  not  break.  It  will  last  for  twenty-five  years,  while  plank  laid 
over  cement  concrete  decays  in  half  the  time  or  less.  The  most 
approved  method  of  laying  a  tar  concrete  floor  is  as  follows : 

After  grading  and  leveling  the  lot  and  filling  soft,  spongy 
places  with  firm  material,  first  spread  a  4-inch  layer  of  screened 
gravel  or  stone  that  has  been  mixed  with  tar,  using  6  to  10  gal- 
lons of  tar  per  cubic  yard  of  stone  or  gravel,  7  gallons  being 
enough  for  coarse  gravel  or  2J-inch  stone,  while  8  to  10  gallons 
of  tar  per  cubic  yard  is  needed  for  J-inch  gravel  or  stone.  The 
tar  should  be  heated  to  200  degrees  F.,  and  only  enough  used  so 
that  the  mixture  can  be  packed.  A  roller  weighing  300  pounds 
per  lineal  foot  has  been  found  satisfactory,  but  tamping  with  iron 
rams  is  sometimes  preferred,  though  a  roller  makes  a  flatter  sur- 
face. In  cold  weather  the  sand  should  be  heated  by  piling  it 
over  and  around  an  iron  pipe  in  which  a  fire  is  kept  burning. 
Over  the  4-inch  layer  of  tar  concrete  is  spread  one  inch  of  dry 
sand,  saturated  with  from  40  to  60  gallons  of  tar  to  the  cubic 
yard.  The  sand  should  be  heated  to  250  degrees  F.  and  the  mix- 
ture spread  \\  inches  thick,  compressed  when  rolled  to  one  inch. 
While  this  top  dressing  is  warm  and  soft,  3-inch  hemlock  plank 
is  laid  upon  it  and  pressed  or  pounded  firmly  down  to  exclude 


GROUND  FLOOES  223 

air  spaces  or  openings,  and  the  edges  of  the  plank  are  toe-nailed 
together;  no  wooden  sleepers  are  required.  A  wearing  surface  of 
tongue  and  groove  yellow  pine  or  maple  is  then  laid  at  right 
angles  to  the  lower  plank  (Fig.  382). 

Cinders  are  sometimes  used  in  place  of  stone  or  gravel  for 
the  lower  course,  but  are  no  saving  over  stone,  for  cinders  require 
15  gallons  of  tar  per  cubic  yard,  or  nearly  twice  as  much  tar  as 
for  stone.  Broken  stone  costs  about  $1.25  per  cubic  yard  and 


i"5and        ^-4  Tar  Concrete  '#  Pitch  I  "5and-J  4  Jarred  Concrete 

Fig.   382.  Fig.   383. 


cinders  50  cents  per  cubic  yard;  but  there  may  be  a  saving  by 
using  cinders  for  railroad  shops  and  round  houses,  because  the 
engines  produce  a  surplus  quantity  and  they  will  cost  little  or 
nothing. 

Sand  without  gravel  or  stone  has  also  been  used  for  the  bottom 
course,  but  is  no  saving  over  stone  or  gravel,  for  sand  requires 
20  gallons  of  tar  per  cubic  yard,  or  more  than  twice  as  much  tar 
as  for  gravel  or  stone.  When  the  ground  is  hard  and  firm,  2  or  3 
inches  of  tarred  stone  may  be  enough,  instead  of  4  inches  as  speci- 
fied above.  Asphalt  is  sometimes  preferred,  because  it  is  mois- 
ture-proof, does  not  evaporate  like  tar  and  is  therefore  more  per- 
manent. These  floors  have  frequently  been  made  by  spreading 
the  top  coating  of  sand  and  tar  over  4  to  6  inches  of  cement  con- 
crete instead  of  over  tar  concrete,  but  tar  concrete  has  proved 
to  be  the  best.  In  other  cases,  a  combination  of  tar  and  pitch  is 
used  instead  of  tar,  using  one  part  of  pitch  mixed  with  two  parts 
of  coal  tar. 

A  floor  of  this  description,  laid  in  a  shop  for  the  Boston  and 
Albany  Railway  Company  in  1898,  with  spruce  for  the  upper 
and  lower  plank  courses,  is  reported  to  have  cost  only  18  cents 
per  square  foot  (Fig.  383).  It  had  a  4-inch  tar  concrete  base 
overlaid  with  sand,  on  top  of  which  was  spread  J-inch  layer  of 
roofing  pitch,  with  double  courses  of  plank,  24  and  1J  inches 
thick,  respectively. 

Another  coal  tar  floor  with  foundations  6  inches  thick,  com- 
posed of  eight  parts  of  cinders  mixed  with  one  part  by  measure 


224:  MILL  BUILDINGS 

of  coal  tar  covered  with  3-inch  plank  on  3  by  4  inch  sleepers,  16 
inches  apart,  cost  8  cents  per  square  foot  for  the  concrete  and  16 
cents  per  square  foot  for  the  wood,  or  a  total  of  24  cents  per 
square  foot.  A  4-inch  base  with  1-inch  sand  covering,  laid  as 
specified  for  Fig.  382,  usually  costs  from  10  to  12  cents  per 
square  foot,  not  including  any  woodwork,  and  the  complete  floor, 
including  wood,  from  25  to  35  cents  per  square  foot.  Coal  tar 
cost  -from  $3  to  $5  per  barrel. 

The  new  shops  for  the  Sturtevant  Company,  at  Hyde  Park, 
Massachusetts,  have  120,000  square  feet  of  tar  concrete  floors, 
with  3-inch  hemlock  plank  laid  in  pitch. 

A  very  satisfactory  shop  floor,  designed  by  Davis  and  Barnes, 
engineers  of  Philadelphia,  was  used  by  them  in  several  build- 
ings for  the  Sessions  Foundry  Company  at  Bristol,  Connecticut 
(Fig.  395).  It  has  a  bottom  layer,  4  inches  thick,  of  well  tarred 
broken  stone,  covered  with  H  inches  of  tarred  sand,  in  which  is 
imbedded  3  by  1J  inch  chestnut  strips  placed  4  feet  apart,  the 
top  of  the  strips  being  level  with  the  sand;  over  this  is  laid  a 
wearing  surface  of  4  by  1J  inch  tongued  and  grooved  maple. 

The  new  plant  of  the  Chapman  Valve  Company  at  Indian 
Orchard,  Massachusetts,  the  repair  shop  of  the  Maine  Central 
Railway  Company  at  Portland  Maine,  and  the  Columbian  Rope 
Company  at  Auburn,  New  York,  all  have  their  main  floors  built 
of  tar  concrete  covered  with  wood. 


BRICK  FLOORS. 

Brick  floors  have  been  generally  adopted  as  standard  construc- 
tion for  railroad  buildings  and  particularly  for  round  houses,  where 
the  pressure  on  the  floor  from  lifting  jacks,  trucks  and  driving 
wheels  is  liable  to  cause  injury.  Wooden  floors  in  round  houses 
wear  out  too  quickly  and  concrete  floors  crack  and  break  under 
the  heavy  loads.  A  good  specification  for  laying  brick  floors  is  as 
follows:  First  excavate  the  soil  to  the  necessary  depth  for  a  solid 
foundation  and  roll  or  tamp  the  ground  thoroughly,  after  which 
one,  two  or  three. layers  of  slag  or  cinders  shall  be  laid  and  rolled, 
each  layer  4  to  6  inches  thick.  The  layers  shall  be  thoroughly 
tamped  and  rolled  before  placing  the  succeeding  one.  Over  the 
cinders  sand  shall  be  spread  to  a  thickness  of  1  to  2  inches, 
depending  on  the  thickness  of  cinder  base  beneath  it,  a  6-inch 
base  having  not  less  than  one-inch  layer  of  sand.  The  sand  shall 


GEOUND  FLOODS  225 

be  thoroughly  rolled  and  smoothed  to  an  even  grade  to  receive  the 
brick.  Hard  vitrified  brick  shall  be  laid  on  edge  with  staggered 

joints  and  an  upper  half -inch  layer  of 

»a3^-^^r£S™£m^^^^      san(^  sPrea^  an<^  r°lle(l.    When  a  water- 
proof floor  is  desired,  the  brick  shall  be 

'^ffiJT ' '"'  'V~  6 ^oS'sia*^'       grouted  with  a  mixture  of  tar  and  pitch, 

Fig  384  "  over  which   is   spread   a   layer   of  sand 

thoroughly  brushed  and  rolled  into  the 

joints.  A  concrete  base  beneath  the  brick  is  preferred  by  some 
railroad  companies  for  their  round  house  floors ;  but  for  shops  with 
lighter  loads,  and  particularly  where  machines  have  special  founda- 
tions, the  concrete  base  is  unnecessary.  Brick  floors  laid  over  a 
cinder  base  cost  from  85  cents  to  $1.15  per  square  yard. 

ASPHALT  FLOOES. 

Asphalt  is  one  of  the  oldest  natural  products  used  in  building 
construction.  Authorities  believe  that  it  was  used  in  building  the 
ark,  the  tower  of  Babel  and  the  walls  of  Babylon.  It  is  stated 
in  Genesis  that  "the  vale  of  Siddom  was  full  of  slime  pits/'  and 
further  that  "they  had  brick  for  stone  and  slime  for  mortar," 
while  in  describing  the  ark  it  is  said  that  "the  ark  was  pitched 
within  and  without  with  pitch."  In  modern  times  asphalt  is  very 
extensively  used  both  for  street  paving  and  floors,  and  is  used  in 
many  monumental  buildings,  such  as  the  Philadelphia  city  hall. 
They  are  very  comfortable  to  walk  upon,  do  not  tire  the  feet 
like  stone,  and  are  serviceable  where  a  low  first  cost  is  not 
the  chief  consideration,  as  the  material  does  not  wear  away,  but 
is  simply  compressed.  These  floors  are  made  by  mixing  crushed 
rock  asphalt  with  Trinidad  asphalt  and  sand  in  the  proportion 
of  60  pounds  of  broken  asphalt  mastic  blocks  with  4  pounds  of 
Trinidad  asphalt  and  36  pounds  of  fine  gravel  and  sand,  the  total 
mixture  weighing  100  pounds.  The  mixture  is  heated  in  kettles 
up  to  400  degrees  F.  for  about  5  hours  and  well  stirred  during 
the  period  of  heating,  after  which  it  is  taken  out  and  spread. 
The  asphalt  mastic,  which  is  sold  in  blocks  weighing  from  50  to 
60  pounds,  contains  86  per  cent  carbonate  of  lime  and  14  per  cent 
of  bitumen,  and  the  blocks,  when  marketed,  bear  the  maker's 
name  or  brand.  Rock  asphalt,  as  distinguished  from  Trinidad 
asphalt,  is  a  limestone  mixed  with  8  to  17  per  cent  of  bitumen, 
and  the  best  is  found  in  workable  quantities  at  Seyssel,  France; 
Limmer.  near  Hanover,  Germany,  and  at  Neuchatel,  Switzer- 


£26  MILL  BUILDINGS 

land.  The  mines  at  Eagusa,  Sicily,  also  produce  a  rock  rich  in 
bitumen,  which  is  largely  used  for  street  paving  in  America.  Beds 
of  sandstone  containing  from  15  to  20  per  cent  of  bitumen  are 
found  in  strata  like  coal  in  several  parts  of  the  United  States, 
notably  near  Santa  Barbara,  California;  in  Utah,  New  Mexico, 
Colorado  and  Kentucky,  and  this  impregnated  sandstone  is  quite 
extensively  used  for  street  paving  in  the  Pacific  States.  The  rock 
asphalt  is  mined,  and  prepared  for  shipping  by  first  grinding  it 
to  powder,  adding  8  per  cent  of  Trinidad  asphalt  to  prevent  burn- 
ing, and  heating  for  five  hours  in  kettles  at  a  temperature  of  350 
degrees  F.  It  should  be  stirred  continuously  during  the  period 
of  heating  and  then  molded  into  blocks  weighing  from  50  to  60 
pounds  each,  known  as  asphalt  mastic.  Asphalt  is  not  volatile  at 
any  natural  temperature,  and  is  therefore  permanent,  but  there 
are  many  imitations  of  asphalt  mastic  made  of  tar  and  crushed 
limestone,  which  are  of  little  value,  for  the  tar  evaporates,  causing 
cracks  and  leaks.  Asphalt  is  not  injured  by  freezing  and  thaw- 
ing, and  should  last  for  ten  years  without  repairing.  It  is  so 
elastic  that  cracks  will  not  form,  is  waterproof,  and  as  it  is  laid 
in  sheets  without  joints,  it  does  not  leak,  and  can  be  kept  clean 
with  a  hose.  Trinidad  asphalt  contains 

Per  Per 

cent.  cent. 

Bitumen    40      Water 17 

Earthy  matter 34 

Vegetable  matter 9  100 

When  taken  from  the  asphalt  beds  in  Trinidad,  it  is  melted  in 
kettles,  which  causes  vegetable  matter  to  rise  to  the  top  and 
earthy  matter  to  settle  to  the  bottom.  The  top  is  then  skimmed 
and  the  pure  asphalt  drawn  off  and  allowed  to  harden. 


k 4' 'Concrete  W*k-4x5"Sleepers~> 

Fig.   385.  Pig.  386. 

For  mill  floors,  one  inch  of  asphalt  is  laid  over  a  foundation 
of  concrete  3  to  4  inches  thick  (Fig.  385)  or  on  boards  covered 
with  sheathing  paper  (Fig.  386).  The  new  locomotive  shops  at 
Parsons,  Kansas,  have  a  portion  of  the  floor  in  the  center  of  the 
shop  made  of  sheet  asphalt.  Eock  asphalt  floors,  not  including 
base,  cost  from  16  to  18  cents  per  square  foot  laid. 


GEOUND  FLOORS  227 

WOOD  FLOORS. 

A  very  substantial  wood  floor  on  which  light  machines  can 
be  placed  anywhere  without  special  foundations  is  illustrated  in 
cross  section  in  Fig.  387.  The  soil  is  first  excavated  to  a  depth 
of  18  inches,  and  after  being  rolled,  and  soft,  spongy  places  filled 
with  hard  material,  an  8-inch  layer  of  cement  concrete  is  spread 
and  rammed.  On  this  is  laid  6  by  6  inch  timbers,  4  feet  apart, 
which  have  been  previously  coated  with  tar  or  liquid  asphalt. 
These  nailing  pieces  are  carefully  leveled  up  to  the  required  floor 
grade  and  the  space  between  them  is  filled  with  a  second  layer  of 
concrete,  covered  on  top  with  a  half  inch  of  lime.  On  these  nail- 

3  "P/ank--;,  .-6x6"        ,-•  Concrete 


.....    -  ..... 
<rf  r*-.  ••>.-.:.  »;».^^».y.-.*.  *»-.  -NT  u  »  ;  *••• 


Fig.  387.  Fig.  388 


ing  pieces  is  laid  3-inch  hard  pine  plank,  toe-nailed  to  sleepers 
and  jointed  with  1  by  1J  inch  splines.  Where  wood  floors  are 
used  the  preservation  of  the  lumber  is  important.  The  method 
of  laying  plank  and  sills  on  a  ^-inch  layer  of  lime  has  been  found 
effective,  and  should  preserve  the  wood  for  fifty  years.  A  more 
recent  method  of  preserving  wood  is  to  lay  plank  and  sills  on  a 
bed  of  sand  and  tar,  pressed  so  tightly  into  the  tar  that  air  is 
excluded  and  dry  rot  prevented.  A  coating  of  rosin  on  the  under 
side  of  plank  and  sills  has  also  been  used  to  prevent  decay. 

A  floor  similar  to  the  above,  but  lighter,  was  used  in  the 
Topeka  shops  of  the  Atchison,  Topeka  and  Santa  Fe  Kailroad 
Company.  No.  1  maple  flooring,  If  inch,  with  1  X  J-inch  splines, 
is  laid  on  3  X  4-inch  yellow  pine  stringers,  placed  18  inches  apart 
and  imbedded  in  6  inches  of  concrete  (Fig.  388). 

The  erecting  shop  of  the  Allis-  Chalmers  Company  at  West 
Allis,  Wisconsin,  has  a  plank  floor  fastened  to  wooden  stringers 
imbedded  in  a  solid  concrete  base  2  feet  thick,  and  is  strong 
enough  to  sustain  heavy  machinery  without  removing  any  part  of 
the  floor  for  special  foundations. 

The  new  shops  of  the  Pittsburg  and  Lake  Erie  Railroad  Com- 
pany, at  McKee's  Rock,  Pennsylvania,  designed  by  Messrs.  A.  R. 
Raymer,  assistant  chief  engineer,  and  B.  A.  Ludgate,  structural 
engineer,  are  illustrated  in  Fig.  389.  The  wearing  surface  is 
tongued  and  grooved  maple  over  a  sub-floor  of  2f-inch 


£28  MILL  BUILDINGS 

yellow  pine,  spiked  to  4x4-inch  stringers  filled  in  between  them 
with  sand.  These  stringers  are  supported  on  4-inch  layer  of 
cement  concrete,  made  of  one  part  of  cement,  five  of  sand  and 
eight  of  broken  stone,  and  over  it  is  placed  five  layers  of  tar 
felt  in  hot  tar,  covered  with  one  inch  of  sand.  At  intervals  of 
5J  feet  there  are  continuous  open  wire  ducts  between  the  nailing 
stringers  for  conveying  electric  power  wires  to  the  machines. 

A  floor  used  in  the  railroad  shops  of  the  Missouri,  Kansas  and 
Texas  Railroad  Company,  at  Parsons,  Kansas,  was  laid  as  fol- 


..4*4  sl'/s Maple    -- 


""slayers Felttyconcrefe   \  3*4"  6 Broken      fSandlTar 

'in  Hot  Tar  layer  Sand  stone 

Fig.  389.  Fig.  390. 

lows :  On  the  ground  was  first  placed  a  6-inch  layer  of  broken 
stone,  covered  with  a  mixture  one  inch  thick  of  sand  and  tar,  on 
which  are  laid  3  X  4-inch  yellow  pine  nailing  pieces  previously 
treated  with  the  zinc  process.  The  spaces  between  these  nailing 
pieces  were  filled  with  dry  sand  and  a  2J-inch  plank  floor  laid 
thereon.  Over  this  is  placed  a  layer  of  roofing  felt,  covered  with 
a  wearing  surface  of  4  X  lj-inch  dressed  white  oak  (Fig.  390). 

A  light  and  cheap  floor  which  was  used  in  the  bridge  shop 
of  the  Pencoyd  Iron  Works  at  Pencoyd,  Pennsylvania,  is  illus- 
trated herewith  (Fig.  391).  The  ground  was  first  leveled  and 
covered  with  a  layer  of  cinders  6  to  8  inches  thick,  in  which  slabs 
or  half-round  timbers  were  imbedded  every  3  feet,  to  which  was 
spiked  a  flooring  of  3-inch  plank.  Both  planks  and  sleepers  are 
coated  on  the  under  side  with  lime  to  assist  in  preserving  the 
wood,  as  noted  before.  This  floor  cost  the  low  price  of  50  cents 
per  square  yard,  but  it  was  light,  and  heavy  machines  required 
special  foundations. 

Illustrations  of  wooden  floors  with  plank  spiked  to  wood  sleep- 
ers, imbedded  in  gravel  or  stone,  are  given  in  Figs.  392,  393  and 
394.  Where  there  are  two  layers  of  plank,  the  upper  ones  should 
be  laid  lengthwise  of  the  shop,  and  these  floors  laid  in  stone  or 
gravel  beds  should  last  five  or  six  years  without  renewing.  Floor- 
ing with  separate  splines  cost  less  than  tongued  and  grooved 
lumber  and  is  therefore  preferable.  The  disadvantage  of  all  wood 
floors  is  that  water  used  in  cleaning  them  is  liable  to  soak  into 
the  wood,  causing  it  to  expand  and  form  ridges. 


GEOUND  FLOORS  229 

TABLE  XXXI. 
COST  OF  WOOD  FLOOKS  (CHICAGO,  1909). 

No.  1  yellow  pine,  2X6  in.,  T.  and  G.,  costs  $8  per  square,  laid. 
No.  1  yellow  pine,  3X6  in.,  T.  and  G.,  costs  $13  per  square,  laid. 
No.  1  yellow  pine,  4X%  in-,  T.  and  G.,  costs  $7  to  $8  per  square,  laid. 
No.  1  yellow  pine,  6X7/s  in.,  T.  and  G.,  costs  $5  to  $6  per  square,  laid. 
White  pine,  4X%  in.,  T.  and  G.,  costs  $8.50  to  $10  per  square,  laid. 
Clear  maple,  2^4X{|  in.,  T.  and  G.,  costs  $11  per  square,  laid. 


,•3  "Plank 


7/8Maole— 


?  PlanK\ 


-  8  "Cinders 

Fig.  391. 


.— -4.0- 

— =s=^ 


"'"•-Gravel 

Fig.  392. 


6  Cinder-'  '4><6 

Fig.  393. 


^"-10  Broken  Stone 

Fig.  394. 


One  man  will  lay  3  squares  of  flooring  per  eight  hour  day  at  the 
ground  level,  or  2^  squares  per  day,  including  hoisting,  on  upper 
floors.  The  cost  of  laying  is  not  proportional  to  the  thickness,  for 
while  3-inch  plank  is  heavier  to  handle,  it  requires  less  care  than 
J-inch  pine  or  maple,  and  the  average  number  of  superficial  feet 
laid  by  one  man  per  day  is  about  the  same  for  thick  flooring  as 


„..- .4  Wood  Blocks 


Fig.  395. 


VXI2  Plank*- Sand 

Fig.  396. 


for  thin.  The  cost  of  laying  2  and  3  inch  plafck  is  frequently 
assumed  at  $4  to  $5  per  thousand,  board  measure.  The  cost  of 
floors  (Fig.  393)  with  lumber  at  $30  per  thousand  is  12  cents 
per  square  foot,  or  16  cents  per  square  foot  with  lumber  at  $40 
per  thousand.  If  laid  over  a  6-inch  base  of  concrete,  instead  of 
cinders,  it  would  cost  from  25  to  30  cents  per  square  foot. 

WOOD   BLOCK   FLOOES. 

A  very  simple  wood  block  pavement  is  made  by  placing  hard- 
wood blocks  4  or  5  inches  thick  on  a  plank  base,  fastened  to 
stringers  bedded  in  sand.  The  freight  car  repair  shop  for  the 


230  MILL  BUILDINGS 

Illinois  Central  Railroad  at  Burnside,  Illinois  (Fig.  396),  has  a 
floor  of  this  description,  made  of  oak  blocks  4  inches  wide,  5 
inches  high,  and  6  to  12  inches  long.  Beneath  the  main  track  rails 
are  12xl2-inch  wooden  stringers. 

A  large  building  for  the  American  Bridge  Company,  at  Am- 
bridge,  Pennsylvania,  designed  under  the  direction  of  Mr.  James 
Christie,  330  feet  wide  and  776  feet  long,  has  for  its  principal 
flooring  a  pavement  of  4  X  4-inch  beech  or  maple  blocks  8  inches 
long,  set  with  the  grain  vertical  on  a  base  of  one-inch  tarred 
sand,  overlying  a  6-inch  base  of  tarred  gravel  (Fig.  397).  The 
site  of  this  building  was  low  and  soft, 

and  the  filling  beneath  the  pavement         ',£ilJl££/lgCg£ff^£L. 
was  covered  with  a   12-inch  laver  of        jjjjj 


well  compacted  cinders.     Cedar  block        -*&/^^^^^^:^^$ 
floors  laid  on  plank  over  a  foundation         -li^  ^^^s^^^^^:?: 

{•*.  •  •'  T'-.'^*_?*-    •*•"-*  ,\.i  .'•*•*.  v'l  '*"•  *  .  •— "-'J  v* 

of  gravel  cost  about  12  cents  per  square       rTorrea^ond  : 5  Tarred  6 ravel. 

foot.    Cost  of  wood  block  flooring  simi-  Fig  397 

lar  to  Fig.   396,  when  made  of  new 

material,  is  18  to  21  cents  per  square  foot,  but  in  railroad  shops 

they  are  sometimes  made  of  old  material,  at  much  less  cost. 

SPECIAL    FLOORS. 

Locomotive  shops  or  car  sheds  require  specially  constructed 
floors  with  pits  4  to  5  feet  deep  between  the  rails,  for  the  purpose 
of  inspection  and  cleaning  the  cars.  The  pits  should  be  well 
crowned  at  the  center  and  drained  so  men  can  work  in  them  with- 
out having  wet  feet.  The  edges  of  the  pits  must  be  capped  at 
either  side  by  longitudinal  timbers,  fastened  to  the  side  walls  and 
to  the  adjoining  floors. 


CHAPTER  XXI. 

UPPER  FLOORS. 
STEEL  TROUGH  FLOORS. 

A  very  solid  floor  is  made  by  laying  one  or  two  courses  of  wood 
flooring  on  sleepers  imbedded  in  the  cinder  filling  of  rolled  steel 
troughs,  resting  either  on  the  top  of  girders  or  framed  into  them* 
(Figs.  398  and  399).  This  floor, 'known  as  the  Lindsay  trough, 
was  first  made  with  uniform  upper  and  lower  sections  (Fig.  399), 
riveted  together  through  their  sloping  webs.  The  shapes  were  not 
satisfactory,  however,  for  on  account  of  the  sloping  connections, 
sections  when  riveted  together,  would  not  be  the  exact  required 
width-,  and  the  trough  connection  holes  would  not  match  the  holes 
in  the  girders.  To  obviate  this  difficulty,  a  joint  was  made  in 
the  upper  section  and  the  two  parts  connected  with  a  cover  plate, 
with  a  slight  provision  for  width  adjustment  by  play  in  the  upper 
rivet  holes.  These  troughs  were  used  for  upper  floors  in  the  fire- 
proof office  building  of  the  Pencoyd  Iron  Works,  and  the  exposed 
metal  ceiling  was  painted  a  light  blue,  adding  greatly  to  the  gen- 
eral light  effect  of  the  rooms.  The  floor  is  laid  on  IJ-inch  matched 
pine,  over  2J  X  3-inch  imbedded  strips. 

The  weight  of  steel  troughs  varies  from  15  to  40  pounds  per 
square  foot,  and  the  safe  load,  from  200  to  2,500  pounds  per  square 
foot,  depending  on  the  span  and  metal  thickness.  Complete  tables 
of  safe  loads  are  given  in  the  hand  book  of  the  Pencoyd  Iron 
Works  and  the  Carnegie  Steel  Company. 

A  form  of  trough  floor,  which  is  now  more  used  than  the  one 
described  above,  is  made  of  plates  and  rectangular  shapes  (Fig. 
400),  Z  bars  being  used  for  smaller  depths.  It  is  very  strong 
and  heavy  and  is  therefore,  more  used  for  bridges  than  for  build- 
ings, though  it  is  occasionally  suitable  for  very  heavy  upper  floors. 

FLAT  PLATE  FLOORS. 

Flat  rolled  steel  or  cast  iron  floor  plates,  roughened  on  the 
upper  surface,  are  much  used  for  cupola  floors  in  foundries  and 
around  iron  furnaces.  The  rolled  steel  floor  plate  of  the  Carnegie 
Steel  Company  is  made  T\  to  J  inch  in  thickness  and  weighs  from 


*  Mill  Building  Construction,  H.  G.  Tyrrell,  1900. 

231 


232 


MILL  BUILDINGS 


13.8  to  21.4  pounds  per  square  foot.  Rolled  steel  floor  plates  are 
thinner  and  lighter  than  cast  iron,  but  the  latter  is  more  com- 
monly used,  especially  for  foundry  charging  floors.  They  are 
stiffer  than  steel  plate  and  are  made  with  a  rougher  surface,  so 
men  walking  upon  them  will  not  slip. 


Fig.  398. 


_JU 


Fig.  399. 


Fig.  400. 

METAL  AECH   FLOORS. 

A  metal  floor  which  is  cheaper  than  the  Lindsay  trough  is 
made  by  placing  curved  sheets  of  corrugated  or  dovetailed  metal 
between  steel  floor  beams,  and  filling  the  space  between  the  curved 
sheets  and  flooring  with  cinder  concrete  in  which  nailing  strips 
are  imbedded  and  carefully  leveled  (Fig.  401).  One  or  two  layers 
of  matched  flooring  are  then 
laid.  The  curved  sheets  serve 
both  as  metal  arches  and  as 
forms  for  the  concrete,  but 
after  the  concrete  is  hardened, 


2  Layers  Flooring^ 

— • — syv»«p..»i 
*&&& 
'• Cinders       *ti      Corr.  Iron 


Fig.  401. 


it  alone  is  enough  to  carry  the 
loads.  Corrugated  iron  arches,  No.  18  gage,  6-foot  span  and 
10-inch  rise,  have  been  tested  to  sustain  1,000  pounds  per  square 
foot.  The  thickness  of  metal  for  use  in  building  floors  depends 
largely  on  the  presence  of  fumes  or  corroding  gases,  and  should  be 
greater  when  these  exist.  No.  20  gage  is  satisfactory  for  ordinary 
use,  and  arches  should  have  a  rise  of  not  less  than  one-twelfth  their 


UPPEE  FLOOES 


233 


span.  The  dovetailed  plates  known  as  Ferrolithic,  made  by  the 
Berger  Manufacturing  Company,  of  Canton,  Ohio,  may  be  used 
instead  of  corrugated  iron.  No.  24  gage  Ferrolithic  cost  $8  to  $10 
per  square  at  the  factory,  and  weigh  163  pounds  per  square. 

A  segmental  floor  arch,  with  beams  10  feet  apart,  and  con- 
crete 3  inches  thick  at  the  center,  will  safely  sustain  a  distributed 


t*B  Corrugated 
Iron  Shutter  ,       , 

Size  of  Building  92.  *300 

Tru55G5-fO-o"cfrs 


concrete  V  Asphalt  on 
Corrugated  IronArcfifo 


tfc 


"i4*l8"  I  \Woodcn- Beams\^Wood  Column^ 


Fig.  402. 


Covering  5 1  ate  on 
B ' Plank 

X 


tool  8unker 


10  c 


147-0 


Fig.  403. 

load  of  250  pounds  per  square  foot,  which  can  be  increased  by 
using  a  greater  thickness  of  concrete  at  the  crown.  Dovetailed 
plates  are  preferable  to  corrugated  iron,  for  this  purpose,  as  they 
may  be  made  partially  fireproof  by  plastering  on  the  under  side. 

Buildings  designed  by  the  author,  with  corrugated  iron  floors, 
are  shown  in  Figs.  402  and  403.     Fig.  403,  a  power  house  design, 


234 


MILL  BUILDINGS 


has  an  engine  room  floor  of  concrete  on  corrugated  iron,  framed 
out  around  the  engine  foundation,  and  cost  56  cents  per  square 
foot  in  place. 

MULTIPLEX  STEEL  PLATE  FLOOK. 

Another  sheet  metal  floor  made  by  the  Berger  Manufacturing 
Company  is  illustrated  in  Figs.  404  and  405.  It  has  2-inch  uni- 
form width  grooves,  and  depths  from  2%  to  4  inches,  and  the 
metal  gages  vary  from  No.  16  to  No.  24.  either  black  or  galvanized. 
It  is  laid  either  on  top  of  floor  beams  or  on  shelf  angles  fastened 
to  the  girder  web,  and  is  filled  with  concrete  in  which  nailing 
strips  are  imbedded.  The  reverse  bends  at  the  top  and  bottom  of 
the  sheets  add  extra  strength.  It  needs  no  center  for  placing, 
but  cannot  be  plastered  below,  and,  like  other  sheet  metal,  must 
be  kept  painted. 

JUIMJIAAA 


Fig.   404. 


Fig.   405. 


TABLE  XXXII. 


SAFE  LOAD  OF  MULTIPLEX  STEEL  PLATE,  WITH  CONCRETE 
FILLING  1  IN.  ABOVE  PLATE. 


Gaye. 

20 

Depth. 

94 

4 

20 

24 

31/. 

?0 

04 

3 

20 

24.. 

2V> 

Weight. 

4. 

6. 

8. 

10. 

18 

1,260 

550 

300 

185 

17.3 

792 

352 

198 

127 

17.5 

1,115 

485 

265 

165 

16 

720 

320 

180 

115 

15.3 

970 

420 

230 

145 

14 

550 

244 

137 

88 

13.4 

675 

295 

160 

100 

12.2 

433 

192 

108 

69 

UPPEE  FLOORS 


235 


TRIANGULAR   SHEET   STEEL   TROUGH. 

A  sheet  metal  trough  is  made  for  floors  of  bridges  and  build- 
ings by  the  Youngstown  Iron  and  Steel  Company,  the  troughs 
for  buildings  being  2J  inches  deep  (Fig.  406).  The  flooring 


Fig.  406. 

weighs  when  laid,  complete  with  concrete  filling  and  IJ-inch  wear- 
ing surface,  from  32  to  35  pounds  per  square  foot.  Like  other 
troughs  or  corrugated  floors,  it  has  twice  the  stiffness  of  a  solid 
floor  containing  the  same  amount  of  filling,  or  it  has  an  average 
thickness  of  filling  of  only  one-half  its  depth  with  the  stiffness 


236  MILL  BUILDINGS 

of  the  full  depth.     The  sheets  are  made  in  lengths  up  to  10  feet, 
with  uniform  width  of  21  inches. 

TABLE   XXXIII. 

WEIGHT  OF  TEIANGULAR  TROUGH  FLOORS.  Lbs. 

per  sq. 

No.  16  gage,  2%  in.  deep,  weight 386 

No.  18  gage,  2%  in.  deep,  weight 313 

No.  20  gage,  2l/2  in.  deep,  weight 241 

No.  22  gage,  2%  in.  deep,  weight 204 

No.  24  gage,  2%  in.  deep,  weight 168 

BRICK  ARCH  FLOORS. 

Brick  arches,  which  were  once  much  used  for  upper  floors,  are 
no  longer  used  to  any  great  extent,  as  brick  or  tile  floors  are  not 
satisfactory  in  buildings  sub- 
ject  to  vibration   from  heavy  , 
machinery.     Moreover,    they 
are  heavy  and  suitable  only  for 
spans  up  to  about  5  feet.    They 
are   made  of  a   single   4-inch 

ring  of  brick  with  a  rise  not  less  than  one-eighth  of  the  span,  and 
are  filled  above  the  arch  with  concrete  in  which  nailing  strips  are 
imbedded  (Fig.  407). 

REINFORCED  CONCRETE  FLOORS. 

In  addition  to  the  floors  made  of  metal  troughs  with  concrete 
filling,  industrial  buildings  frequently  have  reinforced  concrete 
floors  supported  either  on  concrete  or  steel  framing.  Concrete 
framing  is  treated  in  another  chapter  and  the  floor  slabs  only  are 
considered  here.  The  merits  of  concrete  floors  are  well  known. 
They  are  fireproof,  free  from  vibration,  and  clean,  with  no  open- 
ing for  rats  or  vermin. 

A  great  variety  of  concrete  floor  systems  are  in  use,  including 
those  which  have  numerous  joist,  and  others  with  no  joist,  but 
with  thicker  slabs.  Ribbed  floors  with  joist  are  lighter  than  slab 
floors,  but  the  latter  are  thinner  and  give  either  more  head  room 
or  a  less  height  of  building  for  the  same  clear  height  of  stories, 
while  flat  ceilings  are  preferable  to  ribbed  ones  in  case  of  fire. 
Concrete  floors  containing  tiles  are  not  the  best  suited  for  manu- 
facturing buildings  subject  to  the  jars  from  moving  machinery, 
as  the  tiles  are  liable  to  be  loosened. 

It  is  common  practice  in  steel  frame  factory  buildings  to  use 
beams  only  at  the  panels  between  the  columns,  using  a  concrete 
floor,  either  flat  or  ribbed,  in  spans  up  to  15  or  20  feet. 


UPPEE  FLOORS  237 

The  weight  of  a  concrete  floor  depends  on  the  live  load  car- 
ried and  the  system  used,  and  varies  from  60  to  120  pounds  per 
square  foot.  Dry  cinder  concrete  weighs  from  75  to  90  pounds 
per  cubic  foot,  though  it  has  sometimes  been  assumed  as  low  as 
50  pounds. 

Rods,  wire  mesh  and  expanded  metal  are  all  used  for  rein- 
forcing floor  slabs,  the  two  latter  being  most  convenient.  Wire 
mesh  is  economical  on  account  of  its  high  tensile  strength  com- 
bined with  its  elasticity  and  ductility,  and  is  best  suited  for  resist- 
ing tension  stress,  because  the  wires  are  in  straight  lines,  but 
heavy  expanded  metal  has  a  better  union  with  the  concrete.  Soft 
or  medium  steel  bars  are  satisfactory,  but  not  so  convenient  on 
account  of  the  number  of  separate  pieces  to  handle  and  the  diffi- 
culty of  having  them  uniformly  placed;  but  high  tension  brittle 
bars,  resulting  from  cold  rolling  or  roughening,  are  not  reliable. 
Plain  bars  cost  $30  to  $35  per  ton,  while  patented  bars  cost  $40 
to  $45  per  ton.  Triangular  mesh  with  strands  of  No.  4  wire,  4^ 
inches  apart,  united  with  a  diagonal  weave  of  lighter  wire,  weighs 
57  pounds  per  100  square  feet,  and  cost  (in  1909)  $2.30  at  the 
mills.  It  is  shipped  in  rolls  up  to  58  inches  wide  and  600  feet 
long.  No.  10  expanded  metal  with  4-inch  mesh,  which  is  gen- 
erally used  for  flat  reinforcement,  costs  $3.50  per  100  square 
feet.  It  is  economical  in  large  slabs  to  use  tension  members  in 
two  directions  at  right  angles  to  each  other,  and  to  make  the 
slabs  continuous  by  extending  the  metal  over  the  supports  and 
splicing  at  the  point  of  contraflexure,  or  about  one-quarter  of  the 
span  length  from  the  beams. 

The  thickness  of  floor  slab  and  area  of  tensile  metal  depend 
upon  the  loads  and  the  allowable  working  units,  but  in  ordinary 
practice  they  are  quickly  found  from  the  following  original  for- 
mulas, and  the  thickness  will  generally  be  from  4  to  8  inches  : 


1000 

d 

A  =  — 
12 

where  d  is  the  depth  of  slab  from  upper  surface  to  center  of  tension  metal, 
A  =  ,  the  area  of  metal  in  square  inches  per  foot  of  width,  and 
M  =  ,  the  bending  moment  in  inch  pounds. 

Concrete  in  floors  costs  about  $6  per  cubic  yard,  of  which  $1 
to  $1.50  per  yard  is  the  labor  cost  for  placing. 


23S  MILL  BUILDINGS 

Floor  slabs,  4  to  6  inches  thick,  not  including  wearing  sur- 
face, cost  as  follows : 

Concrete    costs 30  to  12  cents  per  sq.  ft. 

Forms  and  labor 8  to  14  cents  per  sq.  ft. 

Steel    5  to     7  cents  per  sq.  ft. 

The  floor  concrete  in  a  large  Kansas  City  building,  from 
observation  by  the  writer,  was  put  in  at  the  rate  of  50  cubic  feet 
of  concrete  per  man  per  day;  under  another  superintendent,  it 
had  been  placed  at  only  half  that  rate. 

The  finish  or  wearing  surface  on  concrete  slab  may  be  either 
one-inch  cement  of  granolithic,  costing  6  cents  per  square  foot, 
or  a  double  layer  of  matched  wood  flooring  fastened  to  sleepers 
imbedded  in  cinders.  Wood  flooring  is  preferred  because  it  is 
more  comfortable  to  stand  and  walk  upon,  and  is  a  better  base  for 
machines.  Matched  factory  maple  flooring,  £  inch  thick,  over 
2-inch  spruce,  costs  13  cents  per  square  foot,  and  |-inch  yellow 
pine,  over  2-inch  spruce,  9  cents  per  square  foot.  Xailing  strips 
or  sleepers  cost  4  cents  per  lineal  foot  in  place,  and  2  to  3  inches 
of  cinder  fill  between  the  strips  cost  3  to  4  cents  per  square  foot. 

The  second  floor  of  the  new  templet  shop  for  the  Pennsyl- 
vania fSteel  Company  has  a  concrete  floor  reinforced  with  expanded 
metal,  supported  on  12-inch  steel  beams  6£  feet  apart  and  20 
feet  long.  Beams  and  girders  are  covered  on  the  under  side  with 
concrete.  This  floor  has  a  IJ-inch  maple  wearing  surface  over  a 
one-inch  sub-floor,  on  3x4-inch  strips,  filled  between  with  cinders. 

The  Fairbanks-Morse  machine  shop  at  Toronto,  Canada,  has 
a  balcony  floor  consisting  of  a  3-inch  concrete  slab,  supported  on 
reinforced  concrete  joist  3  feet  apart.  Beams  are  22  inches  wide 
at  the  top,  6  inches  wide  at  the  bottom,  and  are  reinforced  by  6 
rods,  |£  inch  diameter  each. 

STEEL  GIRDER  AND   TIMBER  FLOORS. 

Several  floors  of  wood  and  steel  combined  are  in  general  use 
for  galleries  or  upper  floors  of  manufac- 
turing buildings,  the  most  common  being      4" 

a  modification  of  wood  mill  construction 

with    steel    beams    capped    with    nailing 

pieces  and  overlaid  with  plank  (Fig.  408).  Fig  408 

This  type  is  accepted   by   the   insurance 

companies  as  a  substitute  for  slow-burning  wood  construction.    The 

beams  must  be  of  the  required  strength  to  support  the  loads  and 


UPPER  FLOORS  239 

the  thickness  of  plank  should  be  as  given  in  Table  XXXIV.  Plank 
should  be  either  shiplap  or  have  tongue  and  groove  or  splines,  the 
last  being  preferable.  Common  practice  is  to  use  plank  3  or  4 
inches  thick,  with  steel  beams  3  to  4  feet  apart,  capped  with  4  or  5 
inch  wood,  hook  bolted  to  the  beams. 

Another  similar  method  (Fig.  409)  had  a  solid  floor  made  of 


|  ^^^  Solid  Plank    ^^^\]    / 

i 

( 

-/ 

1 

1 

. 

y          ^--..-Splice  •*         Tg&nmt 

1 

Fig.  409. 

planks,  laid  on  edge  and  spiked  together,  supported  on  steel  beams. 
The  beam  spacing  should  be  small  enough  so  the  thickness  of  tim- 
ber floor,  which  can  be  found  from  Table  XXXIV,  is  not  excess- 
ive. The  upper  surface  of  the  timber  will  be  somewhat  rough 
and  irregular,  and  may  be  leveled  with  a  J-inch  layer  of  tar 
cement,  made  of  one  part  of  tar  with  one  to  two  parts  of  sand, 
covered  with  a  matched  flooring  of  yellow  pine  or  maple  laid 
while  the  cement  is  soft.  It  is  economical  to  make  the  joints  at 
the  points  of  contraflexure  about  one-quarter  of  the  span  from 
the  beams,  rather  than  by  splicing  over  the  beams,  for  a  condition 
of  continuity  will  then  exist  and  the  floor  will  have  about  25  per 
cent  greater  strength. 

An   arrangement  is   shown  in   Fig.   410   where  heavy   riveted 
floor  girders  are  spaced  10  to  15  feet  apart. 

y  /      and  in  order  to  secure  greater  head  room 

the  wood  joist  rest  on  shelf  angles  riveted 
to  the  girder  web.    The  old  practice  was  to 
space  joist  16  to  20  inches  on  centers,  but 
Fi     410  a  better  way  is  to  use  larger  beams  spaced 

farther  apart.     The  cost  of  the  floor  with 

two  layers  of  pine,  not  including  the  steel  girders,  is  12  to  15  cents 
per  square  foot  in  place. 

Any  of  the  above  wood  floors  may  be  made  more  nearly  fire- 
proof by  adding  a  ceiling  of  metal  lath  and  plaster  beneath  the 
beams,  and  if  additional  fireproofing  is  desired,  an  asphalt  wear- 
ing surface  may  be  used  on  top,  instead  of  the  upper  layer  of  wood. 
Between  double  courses  of  flooring,  one  or  two  layers  of  asbestos 
paper  should  be  laid,  not  only  as  an  extra  fire  precaution  but  to 
prevent  water  used  in  washing  from  running  through.  The  new 
shops  of  the  Sturtevant  Company  have  upper  floors  of  this  con- 


240  MILL  BUILDINGS 

struction,  designed  to  support  250  pounds  per  square  foot,  with 
12x1 6-inch  hard  pine  beams  spaced  4  feet  apart,  resting  on  shelf 
angles  fastened  to  the  web  of  24-inch  rolled  beams. 

SLOW-BUENING  WOOD  FLOOBS. 

The  principle  of  this  construction  is  to  concentrate  wood  mate- 
rial in  large  sizes  to  secure  minimum  surface  exposure.  The 
required  thickness  of  plank  and  the  spacing  of  floor  beams  can 
be  determined  from  the  following  table  for  the  strength  of  plank: 

TABLE  XXXIV. 

SAFE  LOAD  IN  LBS.  PEE  SQ.FT.  FOE  SPEUCE  PLANK  OF  VAEIOUS 
SPANS  AND  THICKNESSES,  FOE  LIMITED  DEFLECTIONS. 


Superficial. 
30     .. 

4. 

09 

5. 
1.2 

6. 
1  4 

7  '. 
1  7 

8. 

1  9 

9. 

9  1 

10. 

94 

11. 
?6 

12. 
9  8 

13. 
3  1 

14. 
34 

40.  . 

1  1 

14 

1  6 

1  9 

99, 

95 

9  8 

30 

39 

35 

38 

50 

1  9 

1.5 

1  8 

9  1 

94 

9  7 

30 

33 

36 

39 

4? 

75 

1  5 

1.9 

?  3 

97 

3  0 

34 

38 

49 

45 

50 

54 

100 

1  7 

22 

?6 

30 

34 

39 

44 

48 

5  1 

56 

6,0 

125  

1  9 

?,4 

?9 

34 

38 

43 

4.8 

53 

5.7 

150  
175  
200  

095 

2.1 
2.3 
2.4 
2  5 

2.6 
2.9 
3.0 
31 

3.1 
3.4 
3.6 
S  8 

3.7 
4.0 
4.2 
44 

4.2 
4.5 

4.8 
51 

4.7 
5.2 
5.4 
56 

5.2 

5.8 
6.0 

5.7 

•  • 

250  
275  
300  
325  
350  
375  
400  

2.7 
2.8 
2.9 
3.1 
3.2 
3.3 
3.4 

3.3 

3.5 
3.6 
3.8 
4.0 
4.2 
4.3 

4.0 
4.2 
4.4 
4.6 
4.8 
5.0 
5.1 

4.7 
4.9 
5.2 
5.4 
5.6 
5.8 
6.0 

5.4 
5.6 
5.9 
6.1 

6.0 

•• 

•• 

•• 

•• 

•• 

Figures  are  based  on  the  formula: 

3  +  L2  (4  P  +  W) 


D  = 


4  E 


where  D  is  depth  of  plank, 

P,  superficial  load  per  sq.  ft., 

W,  weight  of  plank, 

c,  factor  of  6, 

E,  modulus  of  rupture  equals  10,000, 

L,  length  of  span. 

9 

If  yellow  pine  is  used,  take  —  of  thicknesses  given  above. 

10 

Fig.  411  has  5-inch  plank  supported  on  10xl2-inch  beams 
placed  8  feet  on  centers.  The  second  floors  of  the  machine  shop 
and  pattern  storage  buildings  of  the  Sessions  Foundry  Company 
have  3-inch  tongued  and  grooved  yellow  pine  plank  on  12x18- 


UPPER  FLOORS 


241 


inch  yellow  pine  beams.  The  gallery  floors  of  the  Granger  Foundry 
at  Providence,  Rhode  Island  (Fig.  412),  has  a  double  layer  of 
flooring  on  8  X  12-inch  beams  spaced  5  feet  on  centers,  resting  on 
shelf  angles  riveted  to  the  web  of  12-inch  steel  beams  15  feet 


5  Plan  h 


I0"x  /2 "about  8 'C.  to  C. " 

Fig.  411. 


K-- S'O  ""-• 


Fig.  412. 


apart.  The  two  layers  of  floor  plank  should  have  asbestos  or  rosin 
paper  between  them.  If  woodwork  is  painted,  it  should  be  thor- 
oughly dry  and  seasoned  before  paint  is  applied. 

The  cost  of  wood  floor  similar  to  Fig.  412  is  as  follows : 

Per 
square. 

8X12  in.  yellow  pine.  6   ft.  renter  to  center,  costs $  6.50 

Iron   stirrups 3.00 

Anchors 2.50 

3-in.   plank 12.00 

Paper   50 

Factory  maple  flooring 7.00 

Total    .  ..$31.50 


CHAPTER  XII. 

ROOFS— NON-WATERPROOF. 

This  chapter  describes  methods  of  constructing  roofs  of  planks, 
concrete  or  tile,  all  of  which  materials  require  a  roofing  over  them, 
and  the  contents  of  this  chapter  must  not  be  confused  with  the 
later  ones  on  Roofings,  which  describe  materials  with  which  roofs 
are  covered.  The  discussion  here  is  limited  to  roof  construction 
above  the  trusses  and  purlins,  for  the  strength  and  spacing  of 
wood,  steel  and  concrete  purlins  are  considered  under  the  subject  of 
framing. 

An  economic  principle  in  roof  design  is  that  the  roofing  mate- 
rial itself  should  serve  not  only  as  a  covering  and  enclosure,  but 
should  be  capable  of  bearing  its  part  of  the  imposed  loads  and 
transferring  them  by  arch  or  bending  action  to  the  walls  or  trusses. 
Coverings  which  act  as  continuous  beams  above  the  trusses  and 
purlins  are  therefore  better  than  non-continuous  coverings,  and 
long  planks  with  edges  matched  or  splined  and  with  staggered 
end  joints  are  more  economical  than  roofs  made  of  small  dis- 
connected parts,  such  as  flat  tiles  supported  on  purlins. 

WOODEN  EOOFS. 

Wooden  roofs  are  made  of  either  one  or  two  thicknesses  of 
boards  or  planks  supported  on  purlins  or  rafters.  When  slate 
or  shingles  are  used,  with  separate  pieces  held  in  place  by  only 
two  nails  and  nails  in  horizontal  lines,  the  plank  should  then  lie 
parallel  to  the  eave,  so  the  nails  will  never  be  driven  into  cracks 
between  the  boards  and  allow  the  slate  to  become  loosened.  Tar 
and  gravel  or  composition  roofing  in  large  areas  may  have  planks 
laid  in  either  direction,  for  if  occasional  nails  are  then  driven  into 
cracks,  the  covering  will  not  be  loosened.  Planks  should  have 
supports  at  intervals  not  exceeding  about  8  feet,  and  if  trusses  are 
spaced  further  than  8  to  10  feet  apart,  it  is  economical  to  use 
one  or  more  intermediate  jack  rafters  between  the  trusses,  with 
nailing  pieces  bolted  to  their  tops  to  receive  the  roof  boards.  When 
the  roof  covering  is  applied  in  large  sheets  or  areas,  and  planks 
laid  in  the  direction  of  the  slope,  parallel  to  the  gables,  the  planks 
may  then  be  fastened  to  purlins  spaced  4  to  6  feet  apart. 

242 


EOOFS—NON-WATEEPEOOF 


243 


Plank  roofs  are  made  of  one  or  two  thicknesses,  depending 
on  requirements.  Buildings  in  cold  climates,  with  valuable  con- 
tents and  machinery  which  might  easily  be  injured  by  condensa- 
tion water  falling  from  the  roof,  should  preferably  have  two  thick- 
nesses of  roof  boards,  with  a  layer  of  building  paper  between 
them.  An  old  practice  with  double  thickness  roofs  is  to  spread 
a  layer  of  lime  mortar  between  the  boards  to  make  the  roof  a 
better  non-conductor  of  heat  and  more  nearly  fireproof.  If  fire 
should  fall  upon  the  roof  and  burn  the  upper  boards,  the  mortar 
might  then  prevent  fire  from  reaching  the  lower  ones. 

A   very   good   non-conducting   roof   for   northern   latitudes   is 


Fig.  413. 


Fig.   415. 


Fig.  416. 


made  by  laying  Ix2-inch  wood  strips,  spaced  3  or  4  feet  apart, 
between  the  upper  and  lower  layers  of  roof  boards  (Fig.  414). 
This  arrangement  leaves  an  open  air  space  between  the  boards 
and  prevents  heat  from  radiating  through  the  roof.  One  or  two 
layers  of  building  paper  should  be  shingled  over  the  lower  boards 
before  the  strips  are  laid. 

A  very  solid  wooden  roof  is  made  by  placing  2x4  an$  2x6  inch 
wood  on  edge  with  successive  courses  spiked  together,  the  whole 
resting  on  the  rafters  and  bolted  to  them  at  intervals  of  1  or  2 
feet  (Fig.  416),  with  bolt  heads  countersunk  on  the  upper  side; 


244  MILL  BUILDINGS 

the  roof  is  then  covered  with  slag  or  tar  and  gravel.  This  style 
of  roof  can  be  used  for  long  spans,  with  trusses  spaced  farther 
apart  than  is  permissible  with  3-inch  plank  laid  flat,  and  it  requires 
no  framing  of  purlins  or  jack  rafters.  It  is  cheap,  non-condensing 
and  slow-burning  in  construction,  and  can  be  built  by  unskilled 
labor.  The  required  thickness  of  plank  for  different  roof  loads 
and  purlin  spacing  is  given  in  Table  XXXIV. 

REINFORCED  CONCEETE  ROOFS. 

These  roofs  are  made  either  with  separate  slabs  molded  at  a 
factory  and  delivered  to  the  building  ready  for  placing,  or  by  lay- 
ing the  concrete  as  a  solid  monolith  on  the  roof  supported  during 
construction  by  temporary  forms  or  stiffened  expanded  metal. 

Molded  reinforced  concrete  slabs  are  made  in  panels  2  to  3 
inches  thick,  2  to  3  feet  wide,  and  4  to  6  feet  long,  the  length  of 
slab  being  made  to  suit  the  distance  between  rafters.  The  ends 
of  the  slabs  rest  on  the  upper  flanges  of  beam  jack  rafters,  spaced 
4  to  6  feet  apart,  and  the  horizontal  edges  parallel  to  the  eaves 
should  be  tongued  and  grooved  (Fig.  417).  The  vertical  joints 
over  the  jack  rafters  should  be 
filled  with  asphaltic  cement  to 
better  unite  the  separate  blocks 
into  a  solid  roof.  Countersunk 
holes  for  bolts  are  molded  in  the 
concrete  when  the  slabs  are  cast, 
and  they  are  fastened  to  the  roof 
by  means  of  l^XyVinch  band 
iron  clips  and  |-inch  bolts. 
When  completed,  the  concrete  Fig.  417. 

may   be   covered   with   tar   and 

gravel  or  some  form  of  ready  roofing.  Slabs  of  this  kind  were  used 
in  1906  on  the  National  Guard  Armory  at  New  York  City. 

MONOLITHIC  CONCRETE  ROOFS  WITH  FORMS. 

Solid  monolithic  slabs  are  made  by  spreading  concrete  either  on 
flat  expanded  metal  or  wire  mesh  supports  on  temporary  wood 
forms,  or  on  some  kind  of  self-supporting  stiff  expanded  metal 
which  needs  no  forms.  There  is  a  great  variety  of  concrete  sys- 
tems, which  differ  chiefly  in  the  style  of  reinforcement  and  the 
length  of  span.  Many  kinds  of  reinforcement  include  expanded 
metal,  wire  mesh,  rods,  etc.,  and  the  permissible  length  of  slab 


HOOFS— NON-WATERPROOF 


245 


depends  upon  the  thickness.  As  it  is  desirable  to  have  the  loads 
a  minimum,  the  slab  thickness  for  ordinary  roofs  should  not 
exceed  3  inches,  and  this  thickness,  properly  reinforced,  is  strong 
enough  for  lengths  up  to  8  feet. 

All  concrete  roofs  must  be  waterproofed,  and  they  may  be 
covered  with  slate,  tar  and  gravel,  or  tile.  They  are  not  injured  by 
frost  or  cold  weather.  Nails  mav  be  driven  into  the  cinder  con- 


Fig.  418. 


Fig.  419. 

crete  within  two  weeks  after  the  concrete  is  laid,  and,  like  other 
embedded  metal,  the  nails  are  preserved.  Slabs  may  be  laid 
directly  on  rafters  without  purlins  (Fig.  418)  when  truss  spacing 
does  not  exceed  10  feet,  or  on  purlins  between  trusses  (Figs.  419 
and  420)  for  a  greater  truss  spacing.  Fig.  427  shows  the  roof 
on  a  round  house  at  Moose  Jaw,  Canada,  made  of  concrete  and 
expanded  metal  with  a  ceiling  to  prevent  heat  radiation  and  con- 


246 


MILL  BUILDINGS 


densation  on  the  under  side.  The  Coliseum  and  La  Salle  Street 
Station  in  Chicago  have  cinder  concrete  roofs.  Fig.  430  shows 
the  application  of  the  Kahn  system  to  roof  construction. 

Slabs  of  concrete  3  inches  thick, 
reinforced  with  expanded  metal, 
cost,  in  large  areas,  including  con- 
crete and  metal  only,  without  cov- 
ering, 20  to  22  cents  per  square 
foot,  while  smaller  areas  cost  30 
cents  per  square  foot. 

The  American  System  uses  3- 
inch  slabs  weighing  25  pounds  per 
square  foot,  reinforced  with  steel 
rods,  for  lengths  up  to  8  feet  (Fig. 
421),  and  5-inch  slabs  weighing 
39  pounds  per  square  foot,  with  l|-inch  tees,  for  lengths  up  to  16 
feet  (Fig.  423). 


Fig.  420. 


Fig.  421. 


? 'd  Stfel  Boss 


S'ee/ 


Fig.   422. 


HOOFS— NON-WATEKPROOF 


247 


MONOLITHIC  CONCEETE  ROOFS  WITHOUT  FORMS. 

Several  kinds  of  ribbed  or  stiffened  expanded  metal  are  manu- 
factured, and  concrete  can  be  spread  on  these  in  spans  up  to  4  or 


Fig.  423. 

5  feet  without  using  wooden  forms  beneath  them.  Trussit  (Fig. 
424)  made  by  The  General  Fireproofing  Company  is  one  inch 
thick,  and  No.  24  gage  weighs  one  pound  per  square  foot.  The 
sheets  are  made  in  uniform  widths  of  15^  inches  and  lengths  from 
5  to  10  feet,  8  feet  being  standard.  Allowing  4-inch  end  laps 
and  sheets  continuous  over  two  panels,  the  purlin  for  8-foot  sheets 
should  be  spaced  3  feet  10  inches  apart,  and  4  feet  10  inches  apart 
for  10-foot  sheets.  Slabs  only  2  inches  thick  can  be  used  for 

spans  up  to  4  feet,  and  these  light 
concrete  slabs  not  only  make  the 
roof  itself  economical  but  also 
require  a  lighter  frame  than  slabs 
3  or  4  inches  thick.  The  roof  is 
light  in  weight,  fireproof,  re- 
quires no  forms,  and  the  concrete 
adheres  perfectly  to  the  metal 
both  on  the  top  and  bottom.  In 
this  respect  it  is  superior  to  flat 
dovetailed  sheets  where  the  bond 
is  imperfect.  Trussit  metal  costs  5  to  6  cents  per  square  foot  at  the 
factory,  and  2-inch  slabs  complete  on  the  roof,  including  metal, 
cost  15  to  18  cents  per  square  foot.  This  was  used  on  a  large 
building  for  The  Cumberland  Steel  Company  at  Cumberland, 
Maryland. 


Fig.   424. 


248 


MILL  BUILDINGS 


Another  stiffened  metal  lath  made  by  The  Trussed  Concrete 
Steel  Company  is  shown  in  Fig.  425.  The  ribs  are  ^f  inch  high 
and  3J  inches  apart,  and  are  connected  with  flat  expanded  metal. 
The  sheets  are  10 J  inches  wide  and  are  made  in  lengths  from  5 
to  10  feet. 


Fig.  425. 


Fig.   426. 


TABLE  XXXV. 

SAFE  LOAD   IN  LBS.   PEE  SQ.   FT.   FOR  SLABS  WITH   24  GAGE, 
STIFFENED  EXPANDED  METAL  (FIGURE  425). 


Weight       Moment  of        

per  sq.  ft.     resistance.         3.        4.         5.       6.         7.       8. 


Slab  thickness. 

1-in.  slab 12  1,540 

1%-in.  slab 18  2,940 

2-in.  slab 24  4,280 

2y2-in.  slab 30  6,600 

3-in.  slab 36  9,840 

3i/2-in.  slab 42  11,640 


-Span  in  Ft.- 


140  80  52 

272  152  98  68 

394  222  142  98  72 

608  342  218  152  112       86 

910  512  326  228  166     128 

1,080  608  386  270  198     152 


Like  the  one  previously  described,,  it  requires  no  temporary 
forms,  and  the  saving  in  the  centering  more  than  pays  for  the 
expanded  metal.  It  is,  however,  more  difficult  and  expensive  to 
plaster  these  roofs  on  the  under  side  than  to  place  the  concrete 
on  wood  forms,  as  is  done  with  flat  expanded  metal  or  wire  mesh. 

Metal  sheets  in  dovetail  form  are  also  used  as  roof  slab  rein- 
forcement (Fig.  426).  Sheets  are  20  inches  wide  and  5  to  10 
feet  long,  with  corrugations  \  inch  high.  They  are  covered  on 
the  roof  with  \  inch  of  cement  mortar  above  the  metal,  and  an 
equal  thickness  of  plaster  below.  Purlins  should  be  spaced  3 
feet  10  inches  apart  for  8-foot  sheets  and  4  feet  10  inches  for 
10-foot  sheets.  The  metal  must  be  blocked  up  \  inch  above  the 
purlins  on  narrow  strips  of  wood  or  metal  and  fastened  to  them 
with  clinch  nails  or  clips  similar  to  those  used  for  fastening  cor- 
rugated iron.  A  |-inch  thickness  of  concrete  above  the  metal  is 
enough  for  purlin  spacing  not  exceeding  5  feet,  but  for  distances 
of  6,  7  and  8  feet  between  purlins,  the  thickness  of  concrete  above 
the  metal  should  be  f,  \\  and  1|  inches,  respectively.  The  top 
coat  of  mortar  consists  of  one  part  of  Portland  cement  with  four 


ROOFS— NON-WATERPROOF 


249 


parts  of  sand  and  fine  gravel,,  spread  to  a  depth  of  J  inch  over 
the  metal  and  well  worked  into  the  grooves.  Plaster  for  the 
under  side  is  made  by  mixing  two  parts  of  cement  with  four 
parts  of  sand,  and  one  part  of  a  mixture  composed  of  a  pound 


of  hair  to  a  sack  of  lime.  The  mortar  and  plaster  should  be 
allowed  to  harden  for  one  week,  after  which  a  felt  and  gravel 
roofing  may  be  applied.  Slabs  l\  inches  thick  weigh  15  pounds 


Fig.  429. 

per  square  foot,  and  cost,  in  place,  $21  per  square,  though  the 
manufacturers  of  dovetailed  metal  claim  that  it  need  not  cost 
more  than  $16  to  $18  per  square.  This  kind  of  roofing  slab  is 


250 


HILL  BUILDINGS 


not,  however,  very  satisfactory,  for  it  lacks  an  essential  requisite 
of  reinforced  concrete — i.  e.,  that  the  concrete  shall  surround  and 
grip  the  metal  and  not  simply  be  in  contact  with  it.  The  plaster 
on  the  under  side  of  a  large  roof,  inspected  by  the  writer,  and 
covered  with  concrete  slabs  and  dovetailed  metal,  fell,  and  not 
only  covered  and  injured  the  machinery  but  endangered  the  lives 
of  the  workmen. 


Fig.  430. 


TABLE  XXXVI. 

SAFE  LOADS  FOR  CONCRETE  SLABS,  REINFORCED  WITH  METAL 
DOVETAILED  SHEETS. 

(Factor   of   Safety   of  Four.) 
Straight   Sheets,   Twenty-four   Gage,   Depth   of   Corrugation,   One-Half   In. 


Depth  of 
concrete  above 
corrugation. 

Ins. 

3/2 

Dead  load 
per  sq.  ft. 
Lbs. 
16 

Live  I 

Co 

^ad  p 
lan  ir, 
6 
16 
35 
66 
129 
197 
274 
343 
359 
385 
446 

er  sq. 

ft. 

3 
84 
'206 
355 
584 
830 
1,174 
1,506 
1,658 
1,758 
1,868 

4 
52 
110 
191 
296 
461 
634 
726 
880 
944 
1,066 

«/ 

5 
32 
61 
110 
252 
277 
422 
506 
549 
584 
646 

7 

16 
39 
88 
128 
152 
228 
244 
263 
288 

8 

"l 

22 
58 
83 
112 
157 
176 
186 
220 

9 

10 

34 
58 
72 
113 
124 
126 
149 

10 

21 
38 
52 
81 
91 
103 
109 

1    .  . 

30 

2 

36 

42 

3 

48 

3  1/, 

54 

4  .  . 

60 

66 

5  .. 

72 

TILE  ROOFS. 


Hollow  burnt  clay  blocks  or  tiles,  sometimes  called  book  tiles 
because  of  their  shape,  supported  between  lines  of  tees,  are  used 


EOOFS— NON-WATEEPECOF 


251 


for  roofs,  but  they  are  heavy  and  expensive.     The  standard  block 
sizes  are  as  follows,  the  widths  being  uniformly  12  inches: 

12  X  16  X  2  ins. 

12  X  18  X  3  ins. 

12  X  20  X  3  ins. 

12  X  24  X  3  ins. 

12  X  24  X  4  ins. 


LONGITUDINAL  SECTION. 


.rn 


m 


LU 


Fig.  431. 


Blocks  3  inches  thick  weigh  from  13  to  20  pounds  per  square 
foot,  depending  upon  their  porosity  and  the  extent  to  which  they 
are  hollowed  out.  Tees  must  be  placed  one  inch  farther  apart 
than  the  length  of  tiles,  and  as  the  tiles  are  porous,  they  must 
be  covered  with  some  kind  of  roofing.  Nails  can  be  driven  into 
the  tile  as  into  wood.  When  the  tees  need  plastering  or  fire- 
proofing  on  the  under  side,  the  tiles  must  then  be  rabbeted  at 
the  bearings  to  make  a  level  under  surface.  Porous  or  hollow 
tile  prevent  moisture  from  condensing  on  the  under  side,  and 
they  are,  therefore,  used  for  power  houses  and  buildings  contain- 
ing valuable  machinery  which  might  be. injured  by  the  falling  of 
condensation  water. 

A  tile  roof  with  a  7-inch  pitch  and  slate  covering  was  used  on 


BUILDINGS 

the  design  made  by  the  writer,  for  a  foundry  building  at  Copen- 
hagen, Denmark  (Fig.  20).  It  is  also  used  with  five-ply  felt 
covering  on  a  power  house  for  the  Chicago  and  Western  Indiana 
Railway  Company  at  Chicago. 

A  power  house  at  Charlestown,  Massachusetts,  118  feet  wide 
and  92  feet  long,  with  trusses  8  feet  apart,  has  a  roof  of  Guas- 
tavino  cohesive  tile  and  asphalt  covering  (Fig.  279), 


CHAPTER  XXIII. 

ROOFINGS— TILE— SLATE— ASBESTOS— WOOD. 

TILE  HOOFING. 

Roofing  tile  is  much  cheaper  than  it  was  ten  years  ago,  and 
is,  therefore,  having  a  wider  use.  It  is  made  in  a  great  variety 
of  shapes  and  colors — red,  brown,  buff  and  salmon — and  both 
glazed  and  unglazed  (Fig.  432).  The  combination  of  ornamental 
shapes  and  colors  presents  a  more  pleasing  appearance  than  can 
be  secured  with  other  coverings,  but  the  roofing  has  a  higher  cost, 
and,  as  it  is  heavy,  requires  heavier  roof  and  truss  framing  to  sup- 
port it.  It  is  fireproof,  needs  no  painting,  and  is  a  non-conductor 
of  heat  and  electricity. 

Roofs  are  prepared  in  several  ways  for  receiving  tile,  the  most 
common  being  to  sheathe  the  surface  with  boards  and  cover  it  with 
a  layer  of  roofing  paper,  on  top  of  which  are  nailed  strips  of  wood 
1  inch  high  and  2  inches  wide,  spaced  to  suit  the  size  of  tile. 
If  sheathing  is  not  desired,  the  tile  may  be  laid  directly  on  wood 
strips  or  rafters,  or  if  steel  framing  is  used,  the  larger  tile  may 
be  supported  directly  on  angle  iron  purlins  without  sheathing. 
They  are  fastened  to  the  roof  either  by  nailing  directly  to  the 
boards,  with  copper  wire  passed  through  lugs  on  the  under  side 
of  the  tiles  (Fig.  433)  or  with  spring  wire  clips  (Fig.  434). 

Unglazed  tiles  absorb  about  20  per  cent  of  their  weight  of 
water  and  are  liable  to  crack  in  freezing  weather.  To  prevent 
absorption,  they  are  also  made  with  a  glazed  exposed  surface  at  a 
slightly  increased  cost,  the  under  side  remaining  unglazed  or 
porous,  and  any  condensation  forming  soaks  into  the  tile  rather 
than  falling  to  the  floor. 

Interlocking  tiles  make  a  tighter  roof  than  plain  ones,  and  in 
all  cases  the  horizontal  joints  should  be  laid  in  elastic  roofing 
cement,  using  about  40  pounds  per  square,  the  cement  being 
colored  to  match  the  tiles. 

Glass  tiles  are  made  in  the  same  shape  and  size  as  the  usual 
ones,  and  can  be  used  where  skylight  is  desired,  without  breaking 
the  uniformity  of  the  roof  surface.  They  are  laid  and  fastened 
in  exactly  the  same  manner  as  the  ordinary  ones. 

253 


254 


MILL  BUILDINGS 


The  weight  of  roofing  tiles  varies  from  700  to  1,100  pounds 
per  square  and  the  cost  from  $6  to  $30  per  square.  Spanish  tile 
costs,  for  the  material  only,  about  $18  per  square,  or  $22  per 
square  in  place.  Ludowici  tile  costs  from  $7  to  $16  per  square 
for  the  material  only,  and  the  cost  of  laying  varies  from  $2.50  to 
$5  per  square. 


Fig.  432. 


Fig.   433. 

The  new  Atchison,  Topeka  and  Santa  Fe  Eailroad  shops  at 
Topeka,  Kansas,  are  covered  with  Ludowici  tile  laid  on  2  X  2-inch 
wood  strips,  every  fourth  tile  being  fastened  with  copper  wire. 

Reinforced  concrete  interlocking  roofing  tiles  are  made  in  sizes 
26  X  52  inches  with  24  X  48  inches  exposed  to  the  weather.  The 


EOOFINGS— TILE— SLATE— ASBESTOS— WOOD 


255 


concrete  is  J  inch  thick,  strengthened  with  expanded  metal,  permit- 
ting purlin  spacing  of  4  feet  center  to  center,  without  sheathing. 
They  weigh  13  pounds  per  square  foot  and  are  hooked  to  the  purlins, 
lap  2  inches  at  the  side,  4  inches  at  the  ends,  and  are  laid  staggered. 
They  need  no  sheathing,  and  their  cost  as  compared  with  other 
fireproof  roofs  is  quite  low.  It  is  known  as  Federal  Tile. 


Fig.  435. 
SLATE  EOOFING. 

The  best  roofing  slate  in  the  United  States  is  found  near 
Brownville  and  Monson,  Maine,  and  in  the  vicinity  of  Easton, 
Bethlehem  and  Bangor,  in  Pennsylvania,  but  other  grades  are 
found  in  Vermont,  New  York,  and  elsewhere  throughout  the 
country.  The  Peachbottom  and  Bangor  slates  have  long  held  the 
reputation  of  being  unexcelled,  and  are  the  most  expensive. 

The  best  quality  of  slate  has  a  hard  surface,  a  bright  luster, 
and  when  struck  with  the  knuckle  has  a  clear  ring.  Softer  slates 


256 


MILL  BUILDINGS 


give  a  dull  sound  when  struck,  and  as  they  absorb  water  they  are 
liable  to  break  in  frosty  weather,  and  the  nail  holes  wear,  causing 
the  slates  to  loosen.  They  must  lie  flat  on  the  roof  and  should  be 
of  a  uniform  color. 

Slate  is  suitable  when  a  durable,  fireproof  covering  is  desired, 
and  when  laid  on  metal  purlins  without  lining,  there  is  no  com- 
bustible material.  It  cannot  be  used  where  condensation  form- 
ing on  the  under  side  of  the  roof  would  cause  injury  to  the  build- 
ing contents.  It  should  then  be  lined  or  ceiled  underneath. 


SIZE  AND  THICKNESS. 

Slates  are  made  in  sizes  varying  from  6X12  inches  to  16X26 
inches,  or  larger  for  special  cases.  The  large  size  requires  fewer 
purlins,  a  less  amount  of  nails,  can  be  laid  more  quickly  than 
smaller  ones,  and  is  more  suitable  for  mill  and  factory  buildings. 
The  smaller  size  presents  a  more  pleasing  appearance  on  the  roof, 
but  on  manufacturing  buildings  this  is  not  important.  Slates 
are  made  in  thicknesses  varying  from  -J  to  f  inch,  the  usual  being 
about  T3g-  inch. 

The  following  table  shows  the  number  of  roofing  slates  required 
to  lay  a  square,  the  exposure  to  the  weather  on  the  roof  when 
laid  with  standard  3-inch  lap,  the  quantity  of  nails  to  lay  a 
square  and  the  price  per  square  for  carload  lots  on  cars  at  the 
quarry : 

TABLE  XXXVII. 


Exposed  when 

Size  of 

Number  in 

laid,  and 

Nails  to  square, 

Cost  per  sq. 

slate  ins. 

each  square. 

distance  of  lath. 

3d  galvanized. 

at  quarries. 

24X14 

98 

Wy2  ins. 

1  Ibs.    0  ozs. 

$4.20 

24X12 

115 

10%  tins. 

libs.    2  ozs. 

4.45 

22X12 

127 

91/2  ins. 

1  Ibs.    4  ozs. 

4.60 

22X11 

138 

9%  ins. 

1  Ibs.    6  ozs. 

4.70 

20X12 

142 

8^/2  ins. 

1  Ibs.    6  ozs. 

4.80 

20X10 

170 

8y2  ins. 

1  Ibs.  11  ozs. 

5.00 

18X12 

160 

7%  ins. 

1  Ibs.    9  ozs. 

5.00 

18X10 

192 

7%  ins. 

1  Ibs.  14  ozs. 

5.00 

18X   9 

214 

7%  ins. 

2  Ibs.    1  ozs. 

5.40 

16X12 

185 

6%  ins. 

1  Ibs.  13  ozs. 

5.20 

16X10 

222 

6%  ins. 

2  Ibs.    3  ozs. 

5.00 

16X   9 

247 

6%  ins. 

2  Ibs.    7  ozs. 

5.00 

16X   8 

277 

6%  ins. 

2  Ibs.  12  ozs. 

5.00 

14X10 

262 

5%  ins. 

2  Ibs.    9  ozs. 

4.75 

14X   8 

328 

5V2  ins. 

3  Ibs.    3  ozs. 

4.75 

14X   7 

374 

5l/2  ins. 

3  Ibs.  11  ozs. 

4.50 

12X   8 

400 

4%  ins. 

3  Ibs.  15  ozs. 

4.50 

12X   7 

457 

41/2  ins. 

4  Ibs.    8  ozs. 

4.25 

12X   6 

534 

4%  ins. 

5  Ibs.    4  ozs. 

4.00 

BOOFINGS—  TILE— SLATE— ASBESTOS—  WOOD  257 

WEIGHTS  OF  SLATE. 

Solid  slate  rock  weighs  175  pounds  per  cubic  foot.     Slates  of 
various  thicknesses,  therefore,  weigh  as  follows : 


V8   in 1.81  Ibs.  per  sq.  ft. 

&    in 2.71  Ibs.  per  sq.  ft. 

1,4   in 3.62  Ibs.  per  sq.  ft. 

fz   in 4.52  Ibs.  per  sq.  ft. 

%   in 5.43  Ibs.  per  sq.  ft. 

y2   in 7.25  Ibs.  per  sq.  ft. 


The  weight  of  slate  of  various  thicknesses  in  a  square  when 
laid  is  given  by  Professor  Malverd  Howe  in  the  following  table. 
The  length  of  slates  vary  from  12  to  26  inches  and  the  thickness 
from  -J-  to  f  inch.  Ordinary  large  slate  -j\-  inch  thick  will  lay, 
when  on  the  roof,  about  650  pounds  to  the  square. 


TABLE  XXXVIII. 

WEIGHT    OF    SLATE    ROOFING. 


Length 
inins. 

14 
16 
18 
20 
22 
24 
26 


SUITABLE   EOOF   PITCH. 

Large  slates  can  safely  be  laid  with  a  less  pitch  than  smaller 
ones.  The  least  pitch  recommended  for  large  sizes  is  6  inches 
per  foot.  Smaller  ones  should  have  a  pitch  of  7  or  8  inches 
when  laid  without  cement,  but  if  cement  is  used  it  is  then  safe  to 
use  large  slate  on  pitches  as  flat  as  4  inches  per  foot.  On  flatter 
roofs  than  these,  water  is  liable  to  be  blown  up 'under  the  slate 
in  driving  storms  and  leak  into  the  building. 

Slate  is  occasionally  used  as  a  covering  for  tar  or  asphalt  roofs 
on  slopes  that  are  nearly  flat,  but  it  is  merely  as  a  substitute  for 
gravel  covering,  the  waterproofing  being  done  by  the  asphalt 
underneath  it. 


y8  in. 

1%  in. 

li   III   tt/O. 

y±  in. 

(JCI   *y.  1 

%  tn. 

t>.  /  ui  inc  i 

%  in. 

%  in. 

%  in. 

483 

724 

967 

1,450 

1,936 

2,419 

2,902 

460 

688 

920 

1,379 

1,842 

2,301 

2,760 

445 

667 

890 

1,336 

1,784 

2,229 

2,670 

434 

650 

869 

1,303 

1,740 

2,174 

2,607 

425 

637 

851 

1,276 

1,704 

2,129 

2,553 

418 

626 

836 

1,254 

1,675 

2,093 

2,508 

412 

617 

825 

1,238 

1,653 

2,066 

2,478 

407 

610 

815 

1,222 

1,631 

2,039 

2,445 

258 


MILL  BUILDINGS 


METHOD  OF  LAYING  AND  FASTENING. 


Slate  roofing  is  laid  either  directly  on  boards  or  on  wood  or 
metal  purlins,  without  sheathing.  If  sheathing  is  used,  it  should 
be  either  shiplap  or  tongued  and  grooved,  so  no  springing  or  irreg- 
ularities will  occur  to  break  the  slates.  The  boards  or  sheathing 
should  be  covered  with  a  layer  of  building  paper,  to  assist  in  mak- 
ing the  roof  water-tight.  When  laid  on  wood  strips  or  purlins 
(Fig.  436)  these  should  be  from  1  to  2  inches  wide  and  from 
1  to  1J  inches  thick,  supported  on  rafters  and  spaced  the  proper 
distance  apart  to  suit  the  size  of  slats.  Steel  purlins  require  less 
framing  to  support  them,  and  have  the  advantage  of  being  fire- 
proof. Large  slate  24  inches  long  are  most  suitable  for  use  over 
steel  purlins,  which  must  be  spaced  10J  inches  apart. 

The  first  and  last  courses  at  the  eave  and  ridge  must  be  short 


Fig.  436. 

slates,  and  at  the  eave  a  lath  must  be  placed  under  the  lower  edge 
of  slate  to  give  the  same  inclination  as  the  other  ones.  Three 
inches  is  the  standard  lap. 

The  method  known  as  half  slating  (Fig.  437),  in  which  the 
elates  are  spread  apart  equal  to  half  their  width,  is  sometimes 
used  when  great  economy  is  desired,  but  the  roof  is  not  as  tight 
as  when  they  are  laid  close  together. 

Slates  are  fastened  to  the  roof  by  passing  nails  or  wires 
through  holes  in  the  slate  punched  either  at  the  two  upper  corners 
for  connecting  to  the  upper  purlin  or  near  the  middle  for  the 
center  purlin.  In  the  first  method,  the  holes  are  overlaid  by  two 
layers  and  are  therefore  more  nearly  waterproof,  but  the  leverage 
on  the  nails  is  greater,  and  they  are  more  liable  to  break  and 
loosen  from  the  roof.  In  the  latter  method,  with  holes  near  the 


ROOFINGS— TILE— SLATE— ASBESTOS— WOOD  259 

middle,  the  slate  is  held  more  firmly  to  the  roof,  at  the  loss  of  one 
extra  layer  of  shingling.  When  laid  on  boards,  they  are  fastened 
with  galvanized  iron  or  copper  nails.  Black  iron  nails  are  not 
suitable,  as  they  soon  rust  out,  and  the  slate  is  loosened.  The 
fastenings  are  the  weakest  part  of  a  slate  roof,  and  it  is,  there- 
fore, desirable  to  use  the  best  nails  even  at  a  higher  price  to  secure 
permanence.  They  must  not  be  driven  in  too  hard,  for  the  slate 
is  liable  to  be  cracked  or  broken.  Copper  wire  instead  of  nails 
should  be  used  on  metal  purlins.  A  few  courses  at  the  eave  and 
ridge,  and  around  chimneys  or  other  openings,  should  always  be 
laid  in  slater's  cement  to  prevent  leakage,  and  if  the  expense  will 
permit,  it  is  better  to  cement  the  entire  roof.  It  will  make  a 
tighter  roof  and  the  rooms  beneath  will  be  warmer  in  winter  and 
cooler  in  summer.  On  chemical  works  or  wherever  destructive 
gases  or  fumes  are  produced,  cemented  joints  are  imperative,  for 


Fig.  437.  Fig.  438. 

any  kind  of  metal  fastenings  may  be  destroyed,  and  the  cement 
is  needed  to  hold  the  slate. 

Punching  was  formerly  done  by  hand  at  the  building  site,  but 
punching  and  countersinking  the  holes  are  now  done  by  machin- 
ery at  the  quarries,  with  better  results  and  less  loss. 

METHOD  OF  FASTENING  SLATE  DIRECT  TO  STEEL  PURLINS. 

As  the  largest  size  of  slate  manufactured  is  24  inches  long, 
and,  as  a  general  practice,  calls  for  3-inch  minimum  lap  (Fig. 
438),  purlins  should  be  spaced  not  more  than  10J  inches  on  cen- 
ters for  this  size  slate,  and  for  smaller  sizes  in  proportion.  With 
this  spacing,  angle  irons  are  the  most  economical  and  best  shapes 
to  use. 

In  order  to  carry  the  roof  load  as  generally  specified,  viz.,  40 
pounds  per  square  foot,  it  is  not  practical  to  space  trusses  or 
supports  more  than  10  feet  apart  and  use  angle  purlins.  Conse- 
quently, when  it  is  necessary  to  use  a  greater  panel,  jack  rafters 


260 


MILL  BUILDINGS 


can  be  inserted  and  still  have  a  span  of  10  feet  or  less  for  the 
purlin. 

The  general  method  of  fastening  slate  to  purlins  is  to  insert 
either  copper,  lead  or  soft  iron  nails  through  holes  in  the  slate, 
bending  them  over  the  lower  flange  of  the  angle.  The  holes  in 
the  slate  can  be  punched  at  the  quarry,  thus  making  the  spacing 
and  laying  easy. 

The  chief  merit  of  slate  is  its  durability.  Good  slate,  well  laid, 
should  last  from  twenty  to  fifty  years  or  more.  It  is  fireproof 
and  the  smooth  surface  does  not  collect  dust  and  dirt  like  flat  or 


Arrangement  of 

Angle  Purlin 


<  Truss 


Arrangement  of  Steel  Purlins.when 
~      Trusses   are   more  than   10  ft.   C-toC. 


-Jack  Rafte 


f or  ?4" Slate 


erage  Weight  of  Slate 
laid  on  Roof,   6p  Ibs.  per  sq.  /f. 


Fig.  439. 


rough  roofs,  and  water  drained  from  the  roof  is  clean;  but  it  has 
the  disadvantage  of  being  easily  cracked  when  walked  upon  or  by 
excessive  heat,  and  high  winds  ma}'  loosen  pieces  and  blow  them 
to  the  ground,  at  the  peril  of  passers-by.  It  is  also  heavy  and 
expensive,  and  requires  heavier  roof  framing  and  trusses  to  sup- 
port it,  while  the  steeper  pitch  makes  a  greater  roof  area  to  be 
covered.  Slate  is  a  good  conductor  of  heat,  and  unless  there  is 
a  lining  or  ceiling  beneath  it,  the  rooms  will  be  excessively  hot  in 
summer  and  cold  in  winter,  causing  greater  expense  for  heating. 


ROOFINGS— TILE— SLATE— ASBESTOS— WOOD  261 

COST    OF   SLATE   ROOFS. 
Nails  for  fastening  slate  cost  as  follows: 

3d  galvanized  slate  nails  per  keg $5.50 

4d  galvanized  slate  nails  per  keg 5.00 

3d  tinned  slate  nails  per  keg    5.75 

4d  tinned  slate  nails  per  keg    5.25 

3d  or  4d  polished  steel  wire  nails  per  keg 4.00 

Copper  nails  per  pound 20 

Zinc  nails  per  pound 10 

Slaters'  felt  in  rolls  of  6  squares,  per  roll $1.25 

Two-ply  roofing  felt,  per   square 1.00 

Three-ply  roofing  felt,  per  square 1.25 

Slaters'  cement  in  25-lb.  kegs,  per  Ib 10 

Punching  and  countersinking,  large  slates,  per  square 10 

Punching  and  countersinking,  small  slates,  per  square 20 

The  cost  of  common  slates  of  various  sizes  at  the  quarries  is 
given  in  Table  XXXVII.  The  best  slate  at  quarries  costs  from 
$5  to  $7  per  square,  and  red  slate,  from  $10  to  $12  per  square, 
including  punching  and  countersinking.  A  poor  quality  of  black, 
purple  or  mixed  colors  is  sold  at  quarries  for  $2  to  $4  per  square. 

An  experienced  roofer  will  lay  from  1J  to  2  squares  per  day, 
and  the  extra  cost  for  laying  in  cement  is  from  $1.50  to  $2  per 
square.  A  good  roof  of  blue  or  black  slate,  finished  complete, 
will  cost  from  $7  to  $13  per  square,  depending  on  the  quality  of 
slate,  distance  from  the  quarries  and  method  of  laying. 

When  slates  are  punched  at  the  quarry,  they  cannot  be  reversed 
if  corners  are  broken  in  shipping,  and  some  roofers,  therefore, 
prefer  to  hand  punch  the  slates  at  the  site,  even  though  this  costs 
40  cents  per  square,  or  double  the  charge  for  doing  it  at  the 
quarry. 

One  slater  with  half  the  time  of  a  helper  will  lay  three  squares 
of  straight  work  in  8  hours,  two  squares  on  roofs  with  hips  and 
valleys,  or  one  square  on  difficult  or  crooked  roofs. 

The  following  is  a  cost  analysis  per  square  for  slate  roofing, 
assuming  that  a  slater  and  helper  put  on  two  squares  per  day  of 
8  hours : 

Slate,  per  sq $5.00 

Freight,  600  Ibs 2.00 

Loading  and  hauling 20 

Felt  paper  and  nails 20 

Slater,  4  hours  at  40  cents 1.60 

Helper,  2  hours,  at  20  cents 40 

Nails    10 

Total    .  .  .  $9.50 


£62  MILL  BUILDINGS 

If  copper  nails  are  used,  add  60  cents  per  square.  The  cost 
of  freight  will  vary  accordingly  to  location,  while  the  cost  of  haul- 
ing might  be  much  less  in  a  city  than  in  a  rural  district. 

REINFORCED    ASBESTOS    CORRUGATED    SHEATHING. 

This  is  a  comparatively  recent  product,  made  and  laid  similar 
to  corrugated  iron,  but  it  is  much  more  durable.  The  regular 
2j-inch  corrugations  are  made  -fg  inch  thick,  27 -J  inches  wide,  and 
in  lengths  varying  from  4  to  10  feet.  It  is  composed  of  asbestos 
and  Portland  cement  with  a  f-inch  reinforcing  wire  mesh,  com- 
pressed with  heavy  hydraulic  pressure.  It  can  be  cut  or  sawed 
like  wood,  fitted  around  openings,  and  nails  can  be  driven  through 
it  close  to  the  end  or  edge  without  splitting. 

It  needs  no  paint,  becomes  stronger  and  harder  with  age,  and 
will  not  rot  or  rust  like  corrugated  metal.  It  is  very  light,  weigh- 
ing only  2  pounds  per  square  foot,  and  absorbs  only  5  per  cent  of 
its  weight  of  water,  and  can  be  frozen  and  thawed  again  without 
injury.  The  under  side  of  the  sheets  are  rougher  than  the  upper 
side,  and  condensation  does  not  form  so  easily  as  on  metal.  It  is 
water,  fire  and  vermin  proof,  is  not  affected  by  steam,  and  will  not 
decay. 

It  can  be  used  for  roofing,  siding,  partitions,  ceilings,  or  for 
panels  in  fireproof  doors,  and  many  other  places  where  light 
sheathing  is  suitable. 

The  sheets  should  have  a  lap  of  1  or  2  inches  for  siding,  and 
3  to  6  inches  on  roofs,  depending  upon  the  slope.  A  lap  of  3 
inches  is  sufficient  for  an  8-inch  pitch,  but  a  6-inch  pitch,  which 
is  the  least  recommended,  should  have  a  lap  of  6  inches. 

The  maximum  allowable  purlin  spacing  for  roofs  is  30  inches, 
and  for  walls  48  inches. 

TABLE  XXXIX. 
PURLIN  SPACING  FOR  SHEETS  OF  DIFFERENT  LENGTHS. 

Sheets  4  ft.  long  have  purlins  spaced  21  ins.  apart. 
Sheets  5  ft.  long  have  purlins  spaced  27  ins.  apart. 
Sheets  6  ft.  long  have  purlins  spaced  22  ins.  apart. 
Sheets  7  ft.  long  have  purlins  spaced  26  ins.  apart. 
Sheets  8  ft.  long  have  purlins  spaced  30  ins.  apart. 
Sheets  10  ft.  long  have  purlins  spaced  28^  ins.  apart. 

This  roofing  is  fastened  to  steel  roof  purlins  with  bands  and 
clips  similar  to  corrugated  iron  (Figs.  440  and  441).  The  most 
approved  method  is  by  bending  1  by  |  inch  band  iron  around  the 


ROOFINGS— TILE— SLATE— ASBESTOS— WOOD 


263 


purlins,  and  bolting  it  through  the  upper  corrugation  to  the  roof- 
ing sheets  with  stove  bolts  passed  through  1  by  -^  inch  lead 
washers  bent  down  over  the  corrugation.  No.  8  aluminum  or 
copper  wire  passed  through  the  roof  sheets  without  the  use  of 
bolts  may  be  used  instead  of  bands.  The  sides  of  sheets  may  be 
lapped  either  one  or  two  corrugations  as  desired,  the  latter  making 
a  tighter  roof.  The  side  laps  are  bolted  together  with  stove  bolts 
spaced  from  10  to  12  inches  apart.  One  corrugation  side  lap 
gives  an  exposure  of  25  inches  to  the  weather.  A  method  of  fast- 
ening to  wood  purlins  is  shown  in  Fig.  440. 


Fig.  440. 


Fig.  440a. 


TABLE  XL. 
AMOUNT  OF  COKEUGATED   ASBESTOS  EEQUIBED  PER  SQUARE. 

End  lap 1  2  3  4  5  6 

Side  lap,  1  corrugation Ill         112         113         115         116         117 

Side  lap,  2  corrugations 124         125         126         128         129         130 

More  than  600  squares  of  this  material  were  used  on  the  new 
Baldwin  Locomotive  Works  at  Eddystone,  Pennsylvania,  and  it 
is  also  used  on  the  new  buildings  for  the  Indiana  Steel  Company 
at  Gary,  Indiana. 

The  size  with  2^-inch  corrugations  is  sold  at  13 £  cents  per 
square  foot,  f.  o.  b.  works  in  carload  lots,  or  15  cents  per  square 
foot  for  less  than  carloads.  The  cost  of  laying  varies  from  $2.00 
to  $3.00  per  square,  including  nails,  clips,  washers,  etc. 

This  roofing  has  a  high  first  cost,  but  as  it  needs  no  paint  and 
has  little  or  no  maintenance  expense,  the  ultimate  cost  is  no  more 
than  other  first-class  coverings. 

Flat  sheets  of  asbestos  building  lumber,  and  asbestos  shingles 
12  to  16  inches  square  are  made  by  the  same  manufacturers.  The 
building  lumber  is  42  inches  wide,  -J  to  f  inches  thick  and  4  to  8 
feet  long.  The  J-inch  thickness  weighs  1  1-3  pounds  and  costs  10 


264 


MILL  BUILDINGS 


cents  per  square  foot.     The  weights  and  costs  of  other  thicknesses 
increase  in  direct  proportion. 

The  shingles  are  made  in  three  colors,  slate,  gray  and  red,  and 
all  are  manufactured  by  The  Asbestos  Shingle,  Slate  and  Sheath- 
ing Company,  of  Ambler,  Pennsylvania, 


.-^k  Bolts -I'fe  long. 


i  Lead  Washers 


Aluminum  Wire  nof  Suitable 
m  the  Vicinity  of  Saltwater 


No  8  Aluminum  Wire 
66' Per  It)  -^ 


Fig.  441. 

WOOD  SHINGLES. 

Wood  shingles  are  not  used  to  a  great  extent  on  modern  facto- 
ries, but  they  are  noted  here  because  of  their  general  use  on  older 
buildings.  They  are  made  of  cedar,  redwood  or  cypress,  and  sold 
in  bundles  containing  250  standard  size  shingles,  4  by  16  inches, 
or  equivalent.  The  widths  vary  from  4  to  12  inches,  and  the 
thickness  from  -fa  inch  at  the  top  to  -f$  at  the  butt.  They  are 
laid  with  exposure  to  the  weather  varying  from  4  to  6  inches,  4 
inches  being  the  usual  practice.  The  number  required  per  square 
for  various  weather  exposures  is  as  follows: 

4  inches  to  weather  requires  900  shingles   per  square. 
4%  inches  to  weather  requires  800  shingles  per  square. 

5  inches  to   weather  requires  720  shingles   per   square. 

6  inches  to  weather  requires  600  shingles   per   square. 

When  laid  without  mortar,  a  shingle  roof  must  have  a  pitch 
of  not  less  than  6  inches  per  foot,  but  in  mortar  the  pitch  can  be 
less.  They  must  be  laid  with  joints  overlapping  as  nearly  as 
possible  half  the  shingle  width,  and  nailed  at  the  two  upper  cor- 
ners with  galvanized  nails,  two  to  each  shingle,  requiring  5  pounds 
of  nails  per  thousand  shingles. 

The  shingles  are  preserved  by  laying  them   in  mortar  or  by 


EOOFINGS— TILE— XL  ATE— ASBESTOS—  WOOD  265 

coating  them  on  the  under  side  with  lime;  in  the  former  method 
they  are  preserved  by  the  lime  in  the  mortar.  Dipping  the 
shingles  in  stain  before  laying  is  a  good  preservative.,  and  better 
than  painting,  for  the  stain  soaks  into  the  grain  of  the  wood. 

One  man  will  carry  up  and  lay  from  two  to  three  thousand 
shingles  per  day  on  large  plain  surfaces,  or  from  one  to  two 
thousand  on  broken  roof  area.  Cedar  shingles  cost  from  $2.25  to 
$3.50  per  thousand  and  the  cost  of  laying  them  varies  from  $1.00 
to  $2.00  per  square.  An  approximate  cost  per  square  for  shingles 
laid  4  inches  to  the  weather  in  place  is  therefore  as  follows : 

900    shingles    at    $3.00    per    M $2.70  per  square 

Roofing  paper 25  per  square 

Labor  of  laying 1.50  per  square 

Total $4.45  per  square 


CHAPTER  XXIV. 

COMPOSITION  ROOFING. 
TAB  AND  GRAVEL  EOOFING. 

There  are  several  kinds  of  tar  and  gravel  roofing,  differing 
chiefly  in  the  number  of  felt  layers  and  the  amount  and  number 
of  tar  coatings.  The  most  approved  specification  for  a  five-ply 
gravel  roofing  is  as  follows: 

On  the  roofing  boards  first  lay  lengthwise  of  the  roof  a  single 
layer  of  dry  building  paper  weighing  7  to  «10  pounds  per  square, 
the  edges  lapping  2  inches  and  tacked  with  nails  and  tin  washers 
2  feet  apart  (Fig.  442).  Over  this  place  two  layers  of  wool  felt 
36  inches  wide  weighing  not  less  than 
15  pounds  per  square,  shingled  over 
each  other,  with  17  inches  of  each  layer 
exposed,  the  overlapping  17  inches  be- 
ing cemented  with  tar.  Over  this  en- 
tire surface  mop  a  coating  of  hot  tar, 
and  shingle  on  three  more  courses  of 
wool  felt  laid  smooth  and  even,  lapping 
the  courses  as  described  above  with  10 
to  11  inches  of  each  course  exposed. 
The  portion  of  each  course,  10  to  11 
inches  wide  under  the  exposed  surface, 
should  be  cemented  to  the  course  be- 
neath it.  Over  the  finished  felt  layers 
put  on  a  top  coating  of  hot  tar  into 
which  is  rolled  clean  gravel,  free  from 
sand  or  loam,  passed  through  a  f  sieve, 
using  ^  cubic  yard  of  gravel  per  square. 
The  amount  of  tar  or  pitch  used 
should  be  from  8  to  10  gallons  or  100  to  120  pounds  per  square. 
Slag  is  lighter  than  gravel  and  therefore  preferable  for  the 
top  coating. 

A  six-ply  roof  similar  to  the  above  may  be  made  by  lapping 
the  upper  felt  layers  a  greater  distance,  leaving  only  8  inches  of 

266 


Fig.  442. 


COMPOSITION  EOOFING  267 

each  course  exposed.     A  gravel  roof  well  laid  with  good  materials 
should  last  from  15  to  20  years. 

Other  specifications  for  gravel  roofing  require  the  layers  of 
felt  to  be  laid  continuously  with  laps  of  only  6  inches,  the  outer 
8  inches  of  each  layer  being  cemented  to  the  one  beneath  it.  This 
is  simpler  than  first  laying  two  layers  with  17-inch  laps,  covering 
with  asphalt,  and  laying  three  more  layers  of  felt  with  8-inch 
lap,  as  specified  above,  but  the  first  method  is  more  durable. 

A  cheaper  gravel  roof  is  made  by  using  layers  of  heavy  tarred 
paper,  not  cemented  together  but  shingled  over  each  other,  with 
6  to  9  inches  of  each  layer  exposed,  and  applying  over  the  finished 
surface  a  heavy  coating  of  tar  or  pitch.  A  still  cheaper  gravel 
roof  suitable  for  temporary  buildings  may  be  made  by  using  only 
two  or  three  courses  of  felt  instead  of  five,  but  in  any  case  the 
layer  of  dry  building  paper  is  required  against  the  roofing  boards 
to  prevent  tar  leaking  through  the  roof. 

A  tar  and  gravel  roof  requires  a  slope  of  at  least  f  inch  per  foot, 
and  not  greater  than  1  to  1J  inches  per  foot.  If  the  slope  is 
greater  the  tar  will  run  in  hot  weather  and  obstruct  the  gutter  or 
down  spouts,  leaving  parts  of  the  roofing  felt  exposed. 

A  three-ply  gravel  roofing  should  last  from  4  to  6  years,  and 
cost  from  $2.50  to  $3.50.  A  five-ply  gravel  roofing  should  last 
from  8  to  10  years,  and  cost  from  $3.00  to  $5.00.  The  best  gravel 
roofing  should  last  from  15  to  20  years,  and  cost  $7.00. 

These  roof  coverings  are  fireproof,  need  no  painting,  and 
refract  heat,  making  buildings  warmer  in  winter  and  cooler  in 
summer.  They  have  a  small  slope,  and  produce  the  minimum 
area  of  roof  to  cover,  can  be  walked  upon  without  injury  and  are 
noiseless.  They  are  not  effected  by  gas  or  acid,  and  have  a  low 
cost,  making  them  altogether  desirable  for  mill  and  factory  use. 
The  weight  of  finished  roof  varies  from  550  to  650  pounds  per 
square,  and  a  cost  analysis  for  a  five-ply  gravel  roof  is  as  follows: 

Felt  roofing,  75  Ibs.  at  2  cents $1.50  per  sq. 

Pitch,   10   gal.   at    11   cents 1.10  per  sq. 

Gravel,    1/6    yd.,    at    $2.40   per   yd 40  per  sq. 

Nails,  washers,  etc 10  per  sq. 

Labor 80  per  sq. 


Total $3.90  per 


Asphalt  roofing  is  laid  similar  to  a  tar  and  gravel  roof,  except- 
ing that  the  slope  should  not  exceed  -J  inch  per  foot. 

Asphalt  is  superior  to  tar  or  pitch  because  it  does  not  dry  and 


2(58  MILL  BUILDINGS 

peel  or  crack  like  tar,  and  will  not  run  at  any  natural  temperature. 
A  light  three-ply  roof  is  made  as  follows:  One  or  two  layers  of 
dry  paper  36  inches  wide  are  first  laid  lengthwise  of  the  roof  over 
the  sheathing  boards,  with  edges  lapped  17  inches  and  fastened 
with  nails  and  tin  washers.  Over  this  is  mopped  a  coating  of 
asphalt  roofing  cement,  using  10  pounds  or  100  gallons  per  square, 
on  top  of  which  is  laid  a  layer  of  wool  roofing  felt  weighing  not 
less  than  15  pounds  per  square.  A  final  coating  of  asphalt  roof- 
ing cement  is  then  applied,  into  which  is  rolled  clean  gravel 
passed  through  a  f-inch  screen.  If  a  thicker  roofing  is  desired 
an  additional  layer  of  felt  and  asphalt  coatings  may  be  applied. 
When  graveled  it  is  practically  fireproof.  Asphalt  roofing  is  also 
made  in  prepared  form,  and  sold  in  rolls  ready  for  use,  as  de- 
scribed under  "Ready  Roofing." 

PREPARED   OR   READY  ROOFINGS. 

There  are  a  large  number  of  patented  roofings  on  the  market, 
too  many  to  more  than  briefly  mention  here.  Among  them  are: 

Asbestos  Roofing,  made  by  H.  W.  Johns-Manville  Co. 

Asphalt  Roofing,  made  by  Asphalt  Ready  Roofing  Co. 

Asphalt  Sand  Surface,  made  by  Warren  Chemical  &  Manufacturing  Co. 

Carey's  Magnesia  Roofing,  made  by  Philip  Carey  Manufacturing  Co. 

Elaterite  Roofing,  made  by  Western  Elaterite  Roofing  Co. 

Flintkote,  made  by  J.  A.  &  W.  Bird  &  Co. 

Genasco,  made  by  Barber  Asphalt  Paving  Co. 

Granite  Roofing,  made  by  Eastern  Granite  Roofing  Co. 

Lythoid,  made  by  Lincoln  Waterproof  Cloth  Co. 

Maltgoid,  made  by  Paraffine  Paint  Co. 

Monarch,  made  by  Stowell  Manufacturing  Co. 

Paracote,  made  by  Chatfield  &  Wood  Co. 

Paroid,  made  by  F.  W.  Bird  &  Son. 

Ruberoid,  made  by  Standard  Paint  Co. 

Slag  Roofing,  made  by  Warren-Ehret  Co. 

They  are  made  by  cementing  together  layers  of  wool  felt  and 
canvas  with  pitch  or  asphalt,  and  coating  the  exterior  with  fine 
gravel  or  broken  stone,  or  with  fireproof  paint.  They  are  sup- 
plied in  rolls  from  30  to  36  inches  wide,  and  can  be  laid  on  pitch 
roofs  with  edges  lapped  and  fastened  to  the  roof  with  nails  and 
washers. 

Many  of  these  are  excellent  roof  coverings,  and  can  be  placed 
more  quickly  than  ordinary  gravel  roofs,  as  heating  and  melting 
the  cement  or  pitch  in  kettles  is  unnecessary.  They  also  have  an 
advantage  over  the  usual  gravel  roofs  in  being  suitable  for  steep 
pitches  and  can  be  laid  by  unskilled  labor. 


COMPOSITION  ROOFING  269, 

ASBESTOS  ROOFING. 

This  is  a  form  of  ready  roofing,  consisting  of  a  canvas  center, 
coated  on  both  sides  with  waterproof  composition,,  asbestos  felt 
on  top,  and  manila  paper  on  the  bottom.  It  is  laid  lengthwise 
of  the  roof  in  horizontal  courses,  lapped  2  inches  and  cemented 
together,  and  fastened  to  the  sheathing  with  nails  and  tin  washers, 
which  are  coated  with  cement  after  being  driven.  The  whole  is 
then  coated  with  asbestos  paint,  using  one  gallon  per  square,  cost- 
ing 50  cents  per  gallon,  and  it  must  be  repainted  occasionally  as 
required.  The  roofing  weighs  85  pounds  per  square  when  laid, 
and  its  list  price  is  $4.50  per  square.  It  is  fire  and  vermin  proof, 
contains  no  coal  tar,  and  can  be  put  on  by  unskilled  labor. 

Asbestos  cement  for  calking  in  valleys  and  around  openings 
or  chimneys  costs  from  5  to  10  cents  per  pound. 

Asbestos  felts  in  rolls  36  inches  wide  are  used  also  for  gravel 
roofing,  and  like  wool  felts,  are  laid  in  several  courses  shingled 
over  each  other,  with  roofing  cement  between.  The  asbestos  felt 
is  made  in  three  grades,  light,  medium  and  heavy,  weighing  6,  10 
and  14  pounds  per  square,  respectively. 

CAREY'S  ROOFING. 

Carey's  prepared  roofing  is  sold  in  rolls  29  inches  wide,  in 
weights  of  90  and  115  pounds  per  square,  the  former  being  stand- 
ard. With  each  roll  are  2  gallons  of  magnesia  paint,  J  gallon  of 
cement  and  2  pounds  of  nails.  It  consists  of  a  bottom  layer  of 
wool  felt  covered  with  asphalt  cement,  on  which  is  placed  a  layer 
of  burlap  coated  with  elastic  paint,  which  gives  the  appearance 
of  slate  when  dry.  It  is  very  pliable,  is  acid  proof,  and  is  not 
easily  burned.  The  raw  material  costs  about  $3.00  per  square, 
and  laying  50  cents  per  square  additional. 

FLINTKOTE. 

This  is  an  excellent  quality  of  ready  roofing  suitable  fo^  large 
mills  and  factories.  It  is  used  on  the  Birmingham  Union  Station, 
the  Atlanta  Terminal  Depot,  the  Mobile  Terminal  and  elsewhere. 
It  is  proof  against  rats  and  vermin,  and  does  not  need  painting 
more  frequently  than  once  in  two  years.  The  weight  and  cost  of 
the  three  grades  made  are  as  follows : 

1-ply  weighs  35  pounds  per  sq.,  and  costs  $1.80  f.  o.  b.  factory 
2-ply  weighs  45  pounds  per  sq.,  and  costs  2.60  f.  o.  b.  factory 
3-ply  weighs  55  pounds  per  sq.,  and  costs  3.20  f.  o.  b.  factory 


270  MILL  BUILDINGS 

GENASCO'S  ASPHALT  EEADY  EOOFING. 

Asphalt  ready  roofing  in  several  grades,  known  as  Model, 
Stone  Surface,  Whitestone  and  Smooth  Surface,  is  made  by  the 
Barber  Asphalt  Paving  Company. 

Model  has  two  layers  of  felt,  one  of  burlap  and  four  of  asphalt, 
with  a  top  surface  of  crushed  granite,  the  whole  weighing  100 
pounds  per  square.  Stone  Surface  has  two  layers  of  felt  and 
two  of  asphalt  with  a  surface  of  gravel,  and  weighs  120  pounds 
per  square.  Whitestone  has  two  layers  of  felt  and  two  of  asphalt, 
and  is  made  one  and  two-ply,  weighing  60  and  75  pounds  per 
square,  respectively.  Smooth  Surface  is  slate  color,  has  a  single 
layer  of  felt  with  asphalt  coating  on  both  sides.  It  is  made  in 
four  thicknesses,  known  as  -J,  1,  2  and  3-ply,  weighing  25,  35,  45 
and  55  pounds  per  square.  The  two  and  three-ply  are  suited  for 
mill  and  factory  use. 

GEANITE  ROOFING. 

This  is  a  prepared  or  ready  roofing  containing  two  layers  of 
wool  felt  and  two  of  waterproof  composition  with  a  top  dressing 
of  granite  chips.  It  is  sold  in  rolls  32  inches  wide  and  41  feet 
long,  containing  enough  in  each  roll  to  cover  one  square.  With 
each  roll  is  7  pounds  of  cement,  1J  pounds  of  nails  and  instruc- 
tions for  laying,  so  it  can  be  placed  by  unskilled  labor.  It  is  a 
heavy  roofing,  weighing  140  pounds  per  square,  and  costs,  com- 
plete on  the  roof,  from  $2.75  to  $3.75  per  square.  It  is  fireproof, 
needs  no  paint,  and  can  be  laid  on  roofs  with  greater  pitches  than 
2  inches  per  foot.  This  roofing  is  used  on  the  Pennsylvania  Bail-, 
road  Depot  at  Washington,  D.  C.,  the  Lake  Shore  and  Michigan 
Southern  Car  Shops  at  Collinwood,  Ohio,  and  other  large 
buildings. 

GEANITE  EOOFING  SPECIFICATIONS. 

Over  the  roof  boards  lay  two-ply  tarred  roofing  felt  weighing 
not  less  than  40  pounds  per  square  (Fig.  443).  Beginning  at  the 
eaves  run  the  first  sheet  of  felt  parallel  with  the  eaves,  following 
1  inch  to  turn  down  over  the  edge.  Nail  the  upper  edge  of  felt 
with  3-d  barbed  wire  nails  through  tin  washers  12  to  18  inches 
apart,  1  inch  from  the  edge.  The  second  sheet  of  two-ply  felt 
should  be  lapped  10  inches  over  the  first  sheet  in  order  to  break 
joints  with  the  sheets  above  it,  but  the  third  and  all  succeeding 
sheets  of  felt  should  be  lapped  only  2  inches.  After  the  sheets  of 
felt  have  been  laid,  stick  the  joints  with  cement  and  nail  the  edges 


COMPOSITION  EOOFING 


271 


with  3-d  barbed  wire  nails  through  tin  discs  12  to  18  inches  apart. 
After  covering  the  roof  with  two-ply  felt  lay  the  granite  roofing 
parallel  with  the  eaves,  allowing  the  first  sheet  to  turn  down  over 
the  eaves  one  inch.  Draw  the  sheet  out  perfectly  straight  and 
nail  the  upper  edge  of  the  sheet  one  inch  back  from  the  edge  with 
large  head  nails  12  inches  apart.  Lap  the  sheets  three  inches  at 
horizontal  joints  and  four  inches  at  vertical  ones. 

After  the  sheets  of  roofing  are  in  place, 
cement  between  laps  with  roofing  cement 
prepared  and  applied  as  follows :  Heat 
the  cement  in  an  iron  kettle,  having  the 
kettle  free  from  water  or  any  foreign 
substance.  Do  not  use  the  cement  until 
it  is  steaming  hot,  and  then  apply  with 
a  small  mop.  If  the  cement  chills  or  be- 
comes thick  while  using,  heat  it  again, 
as  it  must  not  be  too  thick.  Nail  the 
laps  3  inches  apart  and  1  inch  back  from 
the  edge.  On  roofs  having  less  than  2- 
inch  pitch  per  foot,  cement  between  and 
over  all  laps  or  joints,  but  on  roofs  with 
3  to  6-inch  pitch  per  foot,  it  is  neces- 
sary to  cement  only  between  the  laps  and  joints.  For  pitches  ex- 
ceeding 6  inches  per  foot,  put  cement  between  vertical  joints  only, 
none  being  needed  between  the  horizontal  joints. 

MONARCH  EOOFING. 

A  prepared  asphalt  without  gravel  coating  known  as  Monarch 
Roofing,  made  by  the  Stowell  Manufacturing  Company,  in  one, 
two  and  three-ply,  is  sold  at  $1.50,  $2.00  and  $2.50  per  square, 
respectively,  f.  o.  b.  factory  ready  for  using. 

RUBBER  ROOFING. 

This  consists  of  felt  paper  soaked  in  a  preparation  of  rubber 
and  rolled.  It  has  a  very  low  cost  and  is  useful  principally  for 
covering  temporary  buildings  or  sheds, -which  may  have  as  flat  a 
pitch  as  2  inches  per  foot.  It  is  made  in  widths  of  32  inches  and 
is  laid  lengthwise  of  the  roof  with  layers  overlapping  2  inches. 
It  is  fastened  with  nails  and  tin  washers  or  with  wood  strips 
placed  2  feet  apart,  crosswise  of  the  paper.  After  laying,  it  is 
given  two  coats  of  chocolate-colored  slate  paint,  the  upper  one 
sanded.  The  slate  paint  is  very  elastic,  and  as  it  contains  no  tar 


Fig.  443. 


27?  MILL  BUILDINGS 

it  will  not  crack  or  peel  and  does  not  easily  take  fire.  The  cover- 
ing is  a  non-conductor  of  heat  and  does  not  make  a  hot  upper 
story.  It  costs,  complete  with  nails,  paints  and  sand,  from  $2.50 
to  $3.50  per  square,  depending  on  the  thickness  of  felt  paper  used. 

RUBEEOID   ROOFING. 

Euberoid  is  a  prepared  roofing  consisting  of  heavy  wool  felt 
saturated  with  a  patented  waterproof  composition  and  is  made  by 
the  Standard  Paint  Company.  It  contains  neither  tar,  paper, 
rubber  or  asphalt,  and  is  pliable  and  fireproof,  will  not  dry  or 
crack  nor  run  with  heat,  and  can  be  put  on  roofs  of  any  pitch, 
laying  it  up  over  the  ridge  if  desired.  It  is  laid  with  edges  lapped 
2  inches  and  nailed  through  tin  washers  placed  2  inches  apart, 
which  should  be  covered  with  cement  after  being  driven.  The 
joints  are  cemented  with  "ruberine,"  which  is  applied  without 
heating,  using  J  gallon  per  square. 

The  regular  slate  colored  ruberoid  is  made  in  four  grades,  the 
weights  of  which  costs  f .  o.  b.  factor}-  are  as  follows : 

%-ply>  suitable  for  sheds,  costs     $1.40  per  sq.,  and  weighs  26  Ibs. 

1-  ply,  suitable  for  barns,  costs    1.80  per  sq.,  and  weighs  33  Ibs. 

2-  ply,  suitable  for  warehouses,  costs  .  .  .   2.60  per  sq.,  and  weighs  44  Ibs. 

3-  ply,  suitable  for  mills,  costs    3.20  per  sq.,  and  weighs  54  Ibs. 

A  heavy  quality  similar  to  three-ply  is  also  made  in  red,  brown 
and  green,  costing  $3.20  f.  o.  b.  factory,  and  weighing  50  pounds 
per  square.  The  roofing  needs  no  paint  when  first  applied,  but 
should  be  examined  and  painted  after  two  or  three  years.  The 
rolls  are  36  inches  wide  and  each  roll  contains  enough  nails  and 
ruberine  to  lay  a  square.  The  cost  of  labor  in  laying  it  is  50 
cents  per  square  and  the  total  cost  is  from  $2.50  to  $4.00  per 
square,  complete,  depending  on  the  thickness  used. 


CHAPTER  XXV. 

CORRUGATED  IRON. 

Corrugated  iron  consists  of  thin  sheets  of  flat  metal,  corru- 
gated to  give  it  longitudinal  strength.  It  is  made  in  thicknesses 
from  No.  16,  which  is  TV  inch,  to  No.  28,  which  is  %4  inch 
thick,  and  preserved  by  painting  or  coating  with  zinc  or  lead,  the 
zinc  coating  being  known  as  galvanizing. 

Corrugated  iron  is  a  light  and  cheap  covering,  fire  and  light- 
ning proof,  may  be  quickly  applied,  and  because  of  its  light 
weight  requires  a  correspondingly  light  frame.  When  fastened 
to  the  purlins  or  sheathing  it  adds  stiffness  to  the  entire  building 
frame. 

The  old  method  of  manufacture  consisted  of  rolling  the  cor- 
rugations, but  the  modern  and  better  way  is  to  stamp  each  cor- 
rugation separately,  as  the  sheets  are  then  more  uniform  and  will 
lie  closer  on  the  roof.  As  it  has  no  sharp  joints,  sheet  steel  has 
little  or  no  advantage  over  iron.  Some  makes  of  corrugated  iron 
have  one  edge  of  each  sheet  rolled,  as  shown  in  Fig.  444,  so  there 


Fig.   444. 


Fig.  445. 


will  be  less  spring  or  tendency  to  side  spreading  when  it  is  under 
pressure  or  being  fastened  to  the  roof,  but  the  usual  makes  have 
the  corrugations  turned  down  at  one  side  and  up  at  the  other. 
The  patent  high  edge  raises  the  roofing  at  the  joints  and  gives  a 
paneled  effect. 

Straight  sheets  of  corrugated  iron  are  used  for  walls  and  roofs, 
laid  either  over  boards  or  directly  on  purlins,  and  it  is  suitable 

273 


274  MILL  BUILDINGS 

also  for  ceilings,  fireproof  doors,  shutters,  etc.  Curved  sheets 
riveted  together  at  the  ends  with  large  corrugations  are  used  for 
small  span  roofs  without  any  truss  frames  other  than  angle  skew- 
backs  for  the  arch  sheets  to  thrust  against,  the  skewbacks  being 
tied  together  by  occasional  rods  (Fig.  451).  The  lengths  of  span 
for  which  this  construction  is  suitable  are  given  on  page  120. 
Curved  sheets  are  also  used  for  sidewalk  awnings  (Fig.  445)  and 
for  floor  arches  (Fig.  446). 

PRESERVATION  OF  CORRUGATED  IRON. 

Lack  of  durability  is  the  chief  objection  to  corrugated  iron. 
When  left  in  its  original  condition  with  the  iron  exposed  it  is 
quickly  destroyed  by  rust  and  corrosion.  The  methods  of  pre- 
serving it  are  painting  and  coating  with  either  lead  or  zinc,  the 
latter  method  being  known  as  galvanizing.  If  painted,  it  should 
have  one  coat  of  paint  or  oil  at  the  shop,  and  after  erection  all 
places  that  are  scratched  or  scraped  should  be  repainted  and  the 
entire  surface  given  a  second  coat.  Painting  is,  however,  an 
unsatisfactory  preservative  for  permanent  buildings,  for  it  must 
be  applied  every  year  or  two,  and  even  then  holes  will  appear 
where  the  painted  surface  is  scratched  or  broken.  The  only  satis- 
factory preservative  for  corrugated  iron  is  lead  coating  or  galvan- 
izing. Where  gases  or  chemical  fumes  collect,  painting  is  not 
effective  and  one  of  the  better  preservatives  must  be  used. 

Galvanizing  consists  in  coating  'the  steel  with  a  thin  layer  of 
zinc,  which  adds  -J  of  a  pound  or  about  2J  ounces  for  each  sur- 


Fig.  446.  Fig.  447. 

face  coated,  or  J  of  a  pound  for  both  sides.  It  is  applied  to  the 
sheets  after  corrugating,  so  the  process  of  stamping  will  not  injure 
the  coating.  Galvanized  sheets  should  require  no  painting  for 
four  or  five  years  after  erection,  and  then  when  the  surface  has 
been  weathered,  the  paint  can  be  applied.  Paint  will  not,  how- 
ever, adhere  to  new  galvanized  surfaces,  and  if  painting  is  desired 
immediately  after  erection,  the  surface  of  the  metal  should  be 
brushed  with  a  solution  containing  one  part  of  salamoniac,  one 
part  of  nitrate  of  copper  and  one  part  of  chloride  of  copper,  dis- 


COKKUGATED  IEON 


275 


solved  in  sixty-four  parts  of  water,  to  which  is  added  one  part  of 
hydrochloric  acid.  This  will  turn  the  metal  black  in  12  to  24 
hours,  and  when  dry  the  surface  will  be  ready  for  painting. 
Painted  surfaces  cannot  be  soldered. 

A  large  boiler  shop  designed  by  the  author  for  the  Standard 
Oil  Company  had  the  roof  and  walls  covered  with  lead-coated 
corrugated  iron. 


SIZE  AND  WEIGHT  OF  SHEETS. 

Corrugated  iron  and  steel  is  made  from  flat  sheets,  the  weight 
and  thickness  of  which  are  given  by  the  United  States  Standard 
Metal  Gage,  adopted  by -Congress  in  1893.  The  sheets  are  from 
4  to  10  feet  long,  26  to  27  inches  wide,  depending  on  the  depth 
of  corrugation,  and  are  made  from  flat  sheets  30  inches  wide 
before  corrugating.  The  width  of  corrugation  is  the  distance 
between  centers  of  bends  on  the  same  side  or  the  dimension  D  in 
Fig.  447,  and  the  height  is  the  dimension  h  or  total  thickness. 
Three  sizes  of  corrugations  are  ordinarily  used  for  buildings — 5, 
2^  and  1J  inches — though  3,  f  and  T3e  are  also  made,  but  seldom 
used.  The  2J-inch  corrugation  is  the  standard  for  roofs  and 
walls,  the  1^-inch  being  used  for  doors,  shutters,  partitions  or 


Fig.  448. 

wherever  a  finer  detail  and  better  appearance  is  desired.  The 
5-inch  corrugations  are  used  chiefly  for  heavy  floor  arches  or 
where  curved  sheets  are  used  without  trusses  for  awnings  or  shel- 
ter roofs,  the  larger  and  deeper  corrugations  having  the  greatest 
strength.  The  size  of  corrugations  are  shown  in  Fig.  448.  The 
standard  length  of  sheets  is  8  feet,  which  should  be  used  wher- 
ever possible,  for  they  are  always  kept  in  stock,  but  a  smaller 
stock  of  other  lengths  from  4  to  10  feet  is  also  kept.  The  gages 
commonly  used  for  roof  covering  are  20  and  22,  and  for  walls 
22  and  24. 


276  MILL  BUILDINGS 

TABLE  XLI. 

U.  S.  STANDAED  WEIGHTS  PEE  SQ.  FT.   FOE  METAL  EOOFING, 
21/2-IN.   COEEUGATIONS. 

Thickness                 Flat  sheets  Cor.  sheets. 

Gage                           in  in.               Black.             Galv.  Bla&c.  Galv. 

28     0156                   .63                   .79  .69  .86 

26     0188                    .75                    .91  ,84  .99 

24     0250                 1.00                 1.16  1.11  1.27 

22     0313                  1.25                  1.41  1.38  1.54 

20     0375                  1.50                  1.66  1.65  1.82 

18     0500                 2.00        .         2.16  2.20  2.30 

16     ...                    .   .0625                 2.50                 2.66  2.75  2.91 


TABLE  XLII. 

WEIGHT  PEE  SQUAEE  OF  COBBUGATED  IEON,  PAINTED  — FOE 
VAEIOUS    SHEET    LENGTHS. 

Weight  per  sq.,  laid,  for  lengths  of 

Gage.              5       6       7       8       9  10 

28  83      82      81      80      79  78 

26  101     100      99      98      96  95 

24  134     131     130     128  127  126 

22  166     163     161     159  158  156 

20  198     195     193     190  189  187 

18  264      260      256      254  252  249 

16  331     325     320     318  315  311 

Above  allows  6  in.  end  lap  and  2%  in.  side  lap. 


TABLE  XLIII. 

AMOUNT  OF  COEBUGATED  IBON  EEQUIEED  TO  COVEE  ONE 

SQUAEE. 


End  lap 


1  in.  2  in.  3  in.  4  in.  5  in.  6  in. 

Side  lap  1  corrugation 110  111  112  113  114  115 

Side  lap  iy2  corrugations 116  117  118  119  120  121 

Side  lap  2  corrugations 123  124  125  126  127  128 

2%    in.   is   %   in.   high. 


TABLE  XLIV. 

MEASUREMENTS    OF    COEEUGATED    SHEETS— DIMENSIONS    OF 
SHEETS  AND  COEEUGATIONS. 

Number 

of  cor-  Covering 

rugations  width  of  Width 

Width  of                   Depth  of             to  the  sheet  after  of  sheet   Length  of 

Corrugation.         Corrugation.           sheet,  corrugated,  after  cor.  sheets. 

5      in 1      in.               6  24  in.  27  in.  10  ft. 

21/2  in %  to    %  in.              10  24  in.  26  in.  10  ft. 

114  in %to    Vain.             19%  24  in.  26  in.  10ft. 

%  in %  in.             34%  24  in.  26  in.  8  ft. 


COEEUGATED  IEON  277 

TABLE  XLV. 
CONTENTS  OF  COEKUGATED  SHEETS  AS  FIGURED  IN  SELLING. 


Size  of  cor. 
5       in 

5ft. 

12% 

6ft. 
13% 

14%  * 

7ft. 
15% 

2i/2   in  

11/4   in 

..10% 

•  10% 

13 
13 

15i/6 
15% 

34   in  

10% 

11114 

13 

1414 

15% 

Size  of  cor. 
5       in 

71/2  ft. 

.  .16% 

18 

£1/2  ft.            9  ft. 
19%              20  1/4 

91/2  f*. 
21% 

10ft. 

221/2 

2y2  in  

17  y3 

18%2            191/* 

21% 

1-^4   in  

.  .161/4 

IT  % 

20%2 

21% 

..16% 

The  Moment  of  Inertia,  Section  Modulus,  and  Bending  Mo- 
ment for  corrugated  iron  sheets  are  as  given  by  the  following 
formula : 

Moment  of  inertia,    I  =%5  d2  b  t. 

Section  modulus,         S  =  %5  d    b  t. 

Bending  moment,       M  —  %5  f    d  b  t, 

using  12,000  pounds  as  safe  working  value  for  f 

Safe  uniformly  distributed  load  on  corrugated  iron  sheets  is 
given  by  the  following  formula: 

25,000  b  t  d 
W  =  - 

L 

Where  W  =  total  safe  uniformly  distributed  load  in  pounds, 
L  =  length  of  sheet  in  inches, 
t     =  thickness  of  sheet  in  inches, 
d    =  depth  of  corrugations  in  inches, 
b    =  width  of  sheet  in  inches. 

A  formula  for  the  safe  load  in  pounds  per  square  foot  on 
sheets  of  corrugated  iron,  deduced  from  the  above,  is  as  follows : 

1536  fdt 

W  = X- 


5  L2 

Where  W  =  the  safe  load  in  pounds  per  square  foot. 

STRENGTH  OF  CORRUGATED  IRON. 

Numerous  tests  have  been  made  to  ascertain  the  strength  of 
corrugated  iron  sheets,  and  from  the  result  of  these  tests  formula? 
have  been  prepared.  Tests  made  by  the  Keystone  Bridge  Com- 
pany on  sheets  of  No.  20  gage  and  2J-inch  corrugations  with  a 
clear  span  of  6  feet,  showed  that  the  elastic  limit  was  reached 
under  a  uniform  load  of  30  pounds  per  square  foot,  and  the  ulti- 
mate breaking  load  was  60  pounds  per  square  foot.  Experiments 


278 


MILL  BUILDINGS 


made  by  Mr.  Trautwine  on  5-inch  corrugated  iron,  1  inch  deep, 
No.  16  gage,  with  a  clear  span  of  3  feet  9  inches,  showed  a  safe 
strength  of  350  pounds  per  square  foot  distributed. 

A  development  of  the  formula  is  shown  by  the  chart  in  Fig. 
449,  in  which  the  horizontal  ordinates  are  distances  between  sup- 
ports in  feet,  and  the  vertical  ordinates  are  safe  uniformly  dis- 
tributed loads  in  pounds  per  square  foot. 

The  strength  of  the  metal  itself  can  be  tested  by  bending  a 
piece  and  hammering  it  flat.  If  it  can  be  hammered  out  straight 
again  and  flattened,  the  metal  is  of  good  quality. 


f  =  I20M  Ibs.persaf.  in. 
h  =  height  of  Corrugation 

in  Inches 
t  -  thickness  of  Corrugation 

in  Inches 
I  -  Length  of  Span  in  Inches 


45671 

Span     in      Feet. 
Safe   Load    per  Square    Foot  on    Corrugated  Iron.. 

Fig.  449. 

TABLE  XLYI. 

SAFE  AND  CRIPPLING  LOAD  IN  POUNDS  PER  SQ.  FT.,  RECOM- 
MENDED BY  THE  PENCOYD  IRON  WORKS. 


Gage. 

26 

24.. 


Safe  Load. 
in  feet. — 


3456 
31  23  18  16 
37  28  22  19 


Elastic  Limit. 
—  Span  in  feet. 


34 

44     34     27 


6 
23 


22 48     36     29     24 


20. 


59     44     36     30 


56  42  34  28 
71  54  43  36 
89  67  54  45 


Crippling  Load 

— Span  in  feet. — 

3         456 

69       52     41     34 

84       63     51     42 

107       80     64     54 

134     100     80     67 


COEEUGATED  IEON  279 

PURLIN  SPACING. 

The  proper  purlin  spacing  for  any  given  roof  load  depends  on 
the  supporting  strength  of  the  corrugated  iron  and  can  be  taken 
from  the  chart  (Fig.  449).  Roofs  should  be  proportioned  for 
not  less  than  35  pounds  per  square  foot  in  northern  latitudes,  and 
30  pounds  in  southern  latitudes.  Walls  shoulcl  be  proportioned 
for  10  to  20  pounds  wind  load  per  square  foot,  depending  on 
their  exposure.  The  maximum  allowable  purlin  spacing  for  non- 
continuous  sheets  is  as  follows : 

TABLE  XLVII. 
MAXIMUM  PURLIN  SPACING  FOR  WALLS  AND  ROOFS. 

Walls.  Eoofs. 

No.  26  gage,  maximum  distance  between  purlins.  .3  ft.  6  ins.  2  ft.  6  ins. 

No.  24  gage,  maximum  distance  between  purlins.  .4  ft.  0  ins.  3  ft.  0  ins. 

No.  22  gage,  maximum  distance  between  purlins.  .4  ft.  6  ins.  4  ft.  0  ins. 

No.  20  gage,  maximum  distance  between  purlins . .  5  f t.  0  ins.  4  ft.  6  ins. 

No.  18  gage,  maximum  distance  between  purlins.  .6  ft.  0  ins.  5  ft.  0  ins. 

No.  16  gage,  maximum  distance  between  purlins .  .  7  f  t.  0  ins.  5  ft.  6  ins. 

It  is  preferable,  however,  to  have  sheets  span  the  distance 
between  two  sets  of  purlins,  and  as  10-foot  sheets  are  the  maximum 
length  used,  the  greatest  distance  between  purlins,  after  allowing 
for  a  6-inch  joint  lap,  is  4  feet  9  inches. 

Other   considerations   which   effect  the  purlin   spacing   are   re- 
ferred to  in  Chapter  XIV. 

ROOF  PITCH  FOR  CORRUGATED  IRON. 

A  corrugated  iron  roof  with  sheets  lapping  6  inches  should 
have  a  pitch  of  6  inches  per  foot,  but  in  no  case  should  the  pitch 
be  less  than  4  inches  per  foot  unless  the  joints  are  laid  in  roofing 
cement.  In  any  case  cement  joints  are  desirable,  but  they  are 
unnecessary  where  a  proper  slope  is  given. 

LAYING  CORRUGATED  IRON  ON  ROOFS. 

Nos.  26,  27  and  28  corrugated  iron  are  too  light  to  use  with- 
out lining,  and  must  be  laid  over  sheathing  boards  or  on  strips 
2  feet  apart.  Heavier  gages  may  be  laid  on  boards  or  directly 
on  purlins  unless  the  prevention  of  condensation  is  important,  and 
then  sheathing  may  be  preferred,  although  fireproof  linings  are 
available. 

If  warm  air  or  steam  coming  in  contact  with  the  under  side 
of  roofing  causes  condensation,  or  if  gases  or  corroding  fumes  are 


280  MILL  BUILDINGS 

liable  to  destroy  the  metal,  a  layer  or  two  of  roofing  paper  should 
then  be  placed  over  the  boards.  The  sheets  should  have  an  over- 
lap of  one  corrugation  at  the  sides  when  laid  on  boards,  and  one 
and  one-half  when  laid  directly  on  purlins,  as  shown  in  Fig.  450. 
The  end  lap  should  be  6  inches  for  a  6-inch  pitch  roof,  and  8 
inches  for  4-inch  pitch,  and  the  joints  should  be  coated  with  thick 
metallic  paint  to  prevent  water  from  entering  during  driving 
storms.  If  the  worst  storms  come  from  the  north,  the  north 
sheets  should  be  lapped  on  the  edges  over  the  south  sheets,  and 
vice  versa  if  the  prevailing  storms  come  from  the  south.  Where 
several  sheet  lengths  are  used,  the  longest  should  be  next  the 
eaves,  and  the  shorter  ones  at  the  ridge.  Stamped  corrugated  iron 
can  be  laid  more  quickly  and  easily  than  rolled  sheets,  owing  to 
its  greater  uniformity.  All  fitting  and  cutting  of  sheets  should 
be  done  on  the  building  rather  than  at  the  shop.  Sheets  will 
generally  lay  24  to  24J  inches  to  the  weather.  Curved  sheets 
without  trusses  may  be  used  for  spans  up  to  30  feet  (Fig.  451). 

LAYING  COEEUGATED  IEON  ON  WALLS. 
Nos.  22  or  24  corrugated  iron  is  the  thickness  generally  used 
on  building  sides  when  the  metal  is  fastened  to  steel  purlins,  but 
if  the  walls  are  subject  to  blows,  a  heavier  gage  is  then  preferable. 
The  metal  must  not  touch  the  ground,  but  must  have  a  base 
board  or  concrete  footing  as  shown  in  Fig.  477.  Sheets  on  walls 
should  have  one  corrugation  side  lap  and  4-inch  end  lap.  When 
corrugated  iron  is  fastened  to  wooden  studs  instead  of  purlins 
(Fig.  452),  the  studs  must  be  placed  24  inches  apart. 

FASTENING  COEEUGATED  IEON. 

Side  laps  should  be  riveted  together  with  iron  rivets,  one  to 
two  feet  apart,  or  closer  if  required.  The  end  joints  on  roofs 
must  be  fastened  at  alternate  corrugations,  and  similar  joints  on 
walls  not  more  than  8  inches  apart.  Fastenings  must  pass  through 
the  top  of  corrugation  (Fig.  450),  rather  than  through  the  bot- 
tom. One  maker  specifies  that  when  corrugated  iron  is  laid  on 
boards  there  shall  be  not  less  than  25  6d.  nails  per  sheet,  and 
another  specifies  1J  pounds  per  square. 

The  usual  methods  of  fastening  corrugated  iron  sheets  to  pur- 
lins is  shown  in  Fig.  453.  The  one  marked  A  is  the  most  used, 
because  best  suited  for  angles  and  purlins.  It  consists  of  No.  10 
wire  clinch  rivets  -|  inch  in  diameter  with  a  head  at  one  end, 
driven  through  the  roofing  and  bent  around  the  purlin  on  the 


COEEUGATED  IEON 


281 


under  side.  Angle  purlins  are  used  more  than  any  other  shapes, 
and  clinch  rivets  are  therefore  the  most  common  connection.  A 
more  secure  method  of  fastening  corrugated  iron  to  purlins  is 

shown  in  Fig.  453,  C  to  F,  where 
bands  of  f-inch  hoop  iron  are 
passed  under  the  purlins  and  riv- 
eted or  bolted  to  the  roofing 
sheets.  This  method  is  suitable 
for  purlins  of  any  form — angles, 
channels,  beams  or  Z  bars — but  is 
Fig  450  more  expensive  than  the  method 

shown  in  A. 

Two  men  are  needed  in  making  these  connections,  one  on  the 
roof  and  the  other  below  it  holding  the  riveting  iron  and  bend- 
ing or  clinching  the  wire  nails.  Sheets  should  be  firmly  held  to 
the  frame  so  they  will  not  be  blown  off  or  loosened  by  the  wind. 
A  table  giving  the  required  length  of  clinch  rivets  for  purlin  angles 
of  different  sizes  is  as  follows: 


Fig.  451. 


Fig.  452. 

TABLE  XL VIII. 

SIZE    OF    CLINCH    NAILS    FOE    DIFFEEENT    SIZES    OF    ANGLE 

PUELINS. 

Purlin.  2x2.  2^x3.  3^x3%.  4x4^. 

Length  of  nail 4  5  6  7 

Number  of  nails,  per  lb..-.  .     48  38  33  27 


282 


MILL  BUILDINGS 


The  method  of  fastening  with  J-inch  No.  18  iron  clips,  bolted, 
shown  at  G  and  F,  is  convenient  in  some  places,  but  it  is  not 
secure  and  not  as  desirable  as  the  previous  ones.  Thin  lead  wash- 
ers f  inch  diameter  and  -f^  inch  thick  should  be  used  in  all  cases 
under  the  heads  of  nails  or  bolts,  and  should  be  drawn  tight  against 
the  corrugated  iron  to  prevent  leaks. 


Fig.  453. 

STANDING  SEAM  COEEUGATED  IEON. 

An  improved ' form  of  corrugated  iron  is  now  made  (Fig.  455) 
which  avoids  the  necessity  of  punching  nail  holes  in  the  exposed 
surface,  which  punching  has  always  been  a  weak  feature  of  the 
covering.  The  new  form  has  5-inch  corrugations  and  the  edges 
are  turned  up,  making  standing  seams  1J  inches  high,  over  which 
a  cap  is  placed,  turned  down  one  inch  at  each  side. 


fK  >^~x  x-v^-wtK^ 


Fig.  454. 

The  method  of  applying  is  similar  to  standing  seam  steel  or 
tin  roofing,  using  short  cleats  where  laid  over  roofing  board  and 
long  anchor  cleats  when  laid  directly  on  purlins.  In  the  latter  case, 
the  anchor  or  strap  is  passed  around  the  purlins  and  hooked  over 
the  standing  edges  of  the  two  adjoining  sheets,  which  are  after- 
ward covered  with  a  continuous  cap.  The  cross  seams  are  lapped 
the  same  as  ordinary  corrugated  iron. 


CORRUGATED  IKON  283 

COST  OF  CORRUGATED  IRON. 

Black  or  painted  corrugated  iron  costs  3  cents  per  pound  and 
galvanized  corrugated  iron  3^  cents  per  pound.  The  cost  per 
square  for  United  States  gages  of  both  black  and  galvanized  cor- 
rugated iron  is  therefore  as  given  in  Table  XLIX. 

The  cost  of  corrugated  steel  sheets  is  25  cents  per  square  more 
than  given  in  the  above  table  for  iron.  If  painted  with  asphalt 
or  graphite  paint  instead  of  iron  oxide,  the  price  will  be  increased 
further  by  another  25  cents  per  square.  These  prices  are  for 
small  lots,  and  carloads  will  cost  about  10  per  cent  less.  Curved 


Fig.  455.* 

sheets  cost  20  per  cent  more  than  straight  ones.     Odd  lengths  are 
charged  at  the  price  of  the  next  longest  even  foot. 

Black  wire  clinch  nails  cost 10  cents  per  sq. 

Galvanized  clinch  nails  cost 15  cents  per  sq. 

Cleats  and  bolts  cost 25  cents  per  sq. 

The  cost  of  labor  for  erecting  corrugated  iron  varies  from  $1 
per  square  for  large  areas  and  straight  work  to  $2  or  $2.50  for 
smaller  roofs  or  those  which  require  a  larger  amount  of  fitting, 
and  depending  also  on  the  method  of  attaching  to  the  purlins. 
Bolting  is  cheaper  than  riveting  and  clinch  nails  cheaper  than 
either. 

TABLE  XLIX. 

WEIGHT   AND  COST   OF  CORRUGATED  IRON  PER   SQUARE    (100 

SQ.  FT.). 


Gage. 
28  

Weight  in  Ibs. 
69             ! 

Cost. 

$2.20 

Weight  in  Ibs. 
86 

Cost. 
$3.70 

27  

77 

2.35 

93 

3.75 

26 

84 

255 

99 

3  80 

24  '.. 

Ill 

3.33 

127 

460 

22 

138 

4  10 

154 

5.60 

20  

165 

4.85 

182 

6.40 

18  

220 

6.50 

236 

8.20 

16  

.      ...                 271 

7.30 

286 

9.50 

Extra  charge 

added  to  base  prices  for 

Black 

and  Galvanized  Iron. 

*  From  Gary 

Iron  &  Steel  Co. 

284  MILL  BUILDINGS 

Corrugation $0.05       Goheen  's  carbonizing  coating. .     .30 

Red  oxide  paint 10      Curved  steel 25 

Graphite   20 

ASBESTOS  COVERED  SHEETS. 

Sheets  of  flat  and  corrugated  iron  covered  on  both  sides  with 
asbestos  felt  are  made  by  the  Asbestos  Protected  Metal  Company 
of  Canton,  Massachusetts.  The  asbestos  paper  is  cemented  to 
the  metal  with  pure  black  asphalt  compound,  containing  no  coal 
tar  or  its  products,  equal  in  thickness  to  five  coats  of  paint,  and 
applied  under  pressure  at  a  temperature  of  600  F.  The  covering 
is  made  in  white,  gray  and  terra  cotta  colors,  and  is  suitable  for 
either  driven  into  sheathing  boards  or  hooked  around  steel  purlins, 
partitions. 

Flat  sheets  can  be  laid  parallel  to  the  eave  on  roof  boards  which 
are  either  close  together  or  slightly  separated,  commencing  prefer- 
ably at  the  ridge  to  avoid  soiling  the  sheets  by  working  over  them. 
When  the  roof  has  a  comparatively  flat  pitch,  all  joints  must  be 
cemented,  but  on  steeper  pitches  cement  is  needed  only  at  the 
ends.  Cement  will  adhere  only  when  the  sheets  are  dry,  and  cor- 
rugated sheets  must  be  fastened  through  the  upper  corrugation, 
preferably  with  special  concave  head  nails  made  for  the  purpose, 
either  driven  into  sheathing  boards  or  hooked  around  steel  purlins. 

The  asbestos  covering  is  not  saturated,  and  experiments  by 
the  writer  showed  that  it  resists  fire  while  it  remains  intact,  but 
continued  heat  melts  the  asphalt  paste  under  the  felt,  and  the 
formation  of  gas  loosens  and  breaks  the  covering.  When  fire  has 
once  reached  the  asphalt,  the  covering  is .  quickly  peeled  off  and 
the  asphalt  burns  with  prolific  flame  and  dense  black  smoke. 

Extensive  experiments  were  made  by  the  Pennsylvania  Kail- 
way  Company  at  Jersey  City  to  ascertain  the  value  of  paraffin 
paper  with  paint  as  a  preservative  for  metal.  The  metal  is  first 
coated  with  a  tacky  paint  and  then  covered  with  paraffin  paper, 
which  is  then  painted.  The  experiments  show  it  to  be  a  good 
preservative  against  rust,  especially  in  the  presence  of  salt  water. 

The  manufacturers'  prices,  at  the  factory,  on  2^-inch  asbestos- 
protected  corrugated  metal,  either  white,  gray  or  terra  cotta,  are 
as  follows  (list  subject  to  10  or  15  per  cent  discount)  : 

Per  Per 

square.  square. 

No.   28 $  9.50  No.  22 $13.75 

No.   26 10.25  No.  20 16.00 

No.  24.  .  .    12.25 


CORRUGATED  IRON  285 

ANTI-CONDENSATION  LINING. 

A  lining  should  be  used  under  slate  or  metal  where  condensa- 
tion might  form  and  cause  injury  to  the  building  contents.  When 
the  roof  has  board  sheathing,  one  or  two  layers  of  building  paper 
or  roofing  felt  over  the  boards  are  sufficient,  but  where  slate  or 
metal  is  fastened  directly  to  steel  purlins,  there  must  be  a  sup- 
port for  the  paper  lining.  Some  builders  have  used  a  series  oi? 
separate  wires,  No.  10  gage,  spaced  8  to  12  inches  apart,  cross- 
wise of  the  purlins;  but  a  better  method  is  to  stretch  a  light  wire 
mesh  with  2  to  2%  inch  openings  tightly  over  the  purlins,  the  eave 
and  ridge  purlins  being  trussed,  if  necessary,  to  resist  the  tension 
from  the  wire.  Poultry  netting  has  been  used,  but  it  is  not  the 
best,  for  the  longitudinal  wires  are  not  straight,  and  the  fabric 
will  stretch,  allowing  the  covering  to  sag.  A  better  kind  of  wire 
fabric  is  one  with  straight  longitudinal  wires  connected  by  a  light 
cross  weave.  After  this  is  tightly  stretched  and  fastened  to  the 
purlins,  it  is  covered  with  successive  layers  of  asbestos  and  tar 
paper,  shingled  over  each  other  to  shed  water  which  might  collect 
from  condensation. 

The  composition  of  the  roof  from  the  covering  downward  is  as 
follows : 

1.  Corrugated  iron.  3.     Asbestos  paper. 

2.  Tar  paper.  4.     Wire  netting. 

This  lining  was  used  by  the  writer  on  numerous  buildings 
prior  to  1900,  but  is  not  entirely  satisfactory,  for  leakage  finds  its 
way  through  the  lining  paper  at  the  nail  and  bolt  holes,  and  con- 
densation forms  on  the  bolts  and  clips  beneath  the  wire. 

Another  form  of  condensation  lining  for  corrugated  iron  con- 
sists in  cementing  a  layer  of  asbestos  felt  J  inch  thick  to  the 
under  side  of  the  sheets,  the  lining  following  the  corrugations  of 
the  metal,  and  therefore  having  a  supporting  strength  by  itself. 
The  weak  feature  of  this  lining  is  that  the  cement  softens  when 
water-soaked,  and  the  asbestos  will  peel  off  in  places  and  leave  the 
metal  exposed. 


CHAPTER  XXVI. 

SHEET  METAL  ROOFING. 

Steel  roofing  sheets  are  made  in  standard  lengths  up  to  10 
feet  with  side  seams  formed  at  the  factory  and  are  shipped  in 
crates  ready  for  laying.  Steel  is  preferable  to  iron  because  iron 
would  crack  when  making  the  sharp  bends  at  the  edges  for  join- 
ing the  sheets.  The  metal  should  be  capable  of  being  bent  flat 
and  hammered  down,  straightened  out  and  hammered  flat  again 
in  the  reverse  direction  without  injury,  and  should  be  made  from 
the  best  quality  of  steel.  Sheets  are  28  inches  wide,  and  cover 
24  inches  when  laid.  They  are  made  in  standard  metal  gages,  but 
the  ones  most  used  are  Nos.  24  to  28,  and  are  either  black  or 
galvanized. 

TABLE  L. 

WEIGHT  OP  FLAT  SHEETS  ACCOEDING  TO  THE  UNITED  STATES 
STANDAED  METAL  GAGE  ADOPTED  BY  CONGEESS,  1893. 

Galvanized 

Gage.  Black  Sheets.  Sheets. 

27 68  84 

26 75  90 

24 100  116 

22 125  141 

20 150  166 

18 200  216 

16 250  266 

The  sheets  are  laid  over  laths  or  roofing  boards  covered  with 
a  layer  of  felt  or  heavy  paper  to  deaden  the  noise  and  prevent 
warm  air  from  coming  in  contact  with  the  metal  and  causing  con- 
densation. Tar  paper  is  not  suitable,  as  it  tends  to  cause  corro- 
sion, but  asbestos  paper,  being  fireproof,  is  an  excellent  lining. 

Sheets  should  be  painted  on  the  under  side  before  laying,  and 
then  fastened  to  the  roof  boards  with  metal  clips  placed  12  to  14 
inches  apart.  These  clips  are  nailed  to  the  roof  boards  and  are 
hooked  over  the  standing  seam  which  is  covered  by  the  adjoining 
sheet.  The  grooves  are  lined  with  paraffin  paper  and  closed  with 
roofing  pinchers  so  the  upper  cover  tightly  grips  the  lower  sheet 
(Figs.  456  and  457).  The  cross  seams  are  lock  jointed,  and  as  the 
metal  clips  are  nailed  directly  to  the  boards,  the  roofing  sheets  are 
free  from  nail  holes,  and  in  this  respect  this  style  of  roofing  is 

286 


SHEET  METAL  ROOFING  287 

superior  to  corrugated  iron  or  other  forms  of  roofing  which  are 
fastened  by  nails  through  the  exposed  surface.  The  roofing  is 
suitable  for  any  pitch  greater  than  2  inches  per  foot.  Black 
sheets  should  be  painted  immediately  when  placed  and  every  one 
or  two  years  afterwards.  Galvanized  sheets  may  remain  unpainted 
for  three  or  four  years  without  injury. 


Fig.  456.  Fig.  457. 

Standard  sheets  8  feet  in  length  are  kept  in  stock  by  the 
makers,  and  can  be  delivered  on  short  notice.  On  account  of  the 
large  size  of  sheets,  they  can  be  applied  more  quickly  than  in 
tin  plate  or  shingles  of  smaller  sizes,  requiring  a  larger  amount  of 
erection  labor.  Copper,  lead  and  zinc  sheets  have  all  been  used, 
but  not  extensively  for  mill  or  factory  buildings  because  of  their 
greater  cost.  Sheet  steel  roofing,  either  black  or  galvanized,  is  a 
low  priced  covering,  has  light  weight,  is  water-tight,  lightning 
proof,  and  has  a  low  insurance  rate.  It  weighs,  when  completed, 
only  80  pounds  per  square,  and  costs  $3.50  for  painted  iron  and 
$5.90  per  square  for  galvanized,  erected  and  painted  with  red 
oxide.  These  prices  are  for  small  lots  and  would  be  10  per  cent 
less  for  large  quantities.  Painting  with  graphite  costs  25  cents 
per  square  more  than  red  oxide  painting  quoted  above.  The  man- 
ufacturers of  sheet  steel  and  other  roofings  with  standing  seams, 
furnish  complete  directions  for  laying  and  applying  their  roofing 
and  a  set  of  special  tools  for  making  the  joints. 

STEEL  EOLL  ROOFING. 

This  roofing  is  similar  to  sheet  steel  roofing  and  differs  from 
it  by  having  the  metal  delivered  in  rolls  instead  of  crated  bundles 
(Fig.  458).  When  rolled,  the  side  seams  must  necessarily  be 
made  at  the  site,  and  this  kind  of  roofing  is  therefore  best  suited 
for  roofs  with  flat  pitch,  on  which  the  workmen  can  stand  while 
forming  the  seams.  The  rolls  are  26  inches  wide  and  unless 
otherwise  ordered  are  supplied  in  50-foot  lengths,  with  cross 
seams  factory  jointed,  each  roll  covering  100  square  feet.  When 
desired,  the  rolls  will  be  furnished  in  any  length  up  to  150  feet 
or  of  the  proper  length  to  lay  over  the  ridge  from  eave  to  eave 


288 


MILL  BUILDINGS 


without  joining.  Excepting  that  the  standing  seams  for  roll 
roofing  are  made  on  the  roof  or  at  the  building  site,  the  general 
method  of  applying  it  is  similar  to  that  already  described  for 
sheet  steel  roofing,  and  the  weight  and  cost  are  also  about  the 
same.  The  freight  charges  are  less  for  shipping  steel  in  rolls 
than  in  crates,  because  there  is  no  freight  to  pay  on  the  crating 


Fig.  458. 

lumber;  to  offset  this  saving,  there  is  an  increased  labor  cost  in 
forming  the  standing  seams  by  hand  labor  on  the  building  instead 
of  forming  by  machinery  at  the  shop.  When  roofs  have  a  pitch 
of  3  inches  per  foot  or  more,  it  is  more  convenient  to  use  sheets 
with  factory-made  standing  seams,  and  when  the  sheets  pass  over 
the  ridge,  no  capping  is  needed. 

V  CEIMPED  EOOFING. 

This  is  another  sheet  steel  roofing  supplied  either  in  black  or 
galvanized,  in  widths  of  28  inches  and  lengths  up  to  10  feet. 
Instead  of  having  standing  seams  for  side  joints,  the  edges  are 
crimped  in  V  shape  (Fig.  459),  and  lap  over  each  other,  being 


Fig.   459. 


Fig.   460. 


nailed  to  triangular  wood  strips  on  the  roof.  It  can  be  laid 
directly  over  wood  rafters  without  sheathing,  and  when  so  laid 
is  one  of  the  cheapest  roof  coverings  on  the  market.  When  sheath- 
ing is  not  used,  the  rafters  must  be  spaced  2  feet  apart  on  cen- 


SHEET  METAL  EOOFING  289 

ters,  with  strips  framed  between  them  level  with  the  rafter  tops, 
spaced  to  suit  the  cross  joints  (Fig.  460).  Intermediate  cross 
pieces  midway  between  the  horizontal  seams  should  be  used  when 
sheets  are  long,  to  prevent  them  from  sagging.  A  lining  of  asbes- 
tos paper  or  felt  should  be  laid  over  the  boards  wherever  condensa- 
tion may  occur.,  and  unless  extreme  economy  is  desired,  better 
results  are  obtained  by  laying  the  metal  on  sheathing  boards 
instead  of  open  rafters.  It  is  easily  and  quickly  applied,  as  one 
man  can  lay  from  8  to  10  squares  per  day.  Sheets  lay  24  inches 
in  width  and  are  nailed  through  the  inclined  edges  into  the  trian- 
gular strips  of  wood.  When  received  at  the  building,  the  ends  are 
clipped  ready  for  Jock  jointing,  and  at  the  eave  the  sheets  are 
bent  down  and  nailed  over  the  edge  board.  This  form  of  roofing 
is  suitable  for  roofs  with  a  minimum  pitch  of  2  inches  per  foot, 
and  can  be  used  on  steeper  pitches  if  desired.  No.  27  gage 
weighs  83  pounds  per  square  and  in  small  quantities  costs  $3.10 
per  square  for  painted  sheets,  or  $5.50  per  square  for  galvanized 
sheets. 

METAL  SHINGLES. 

These  are  not  extensively  used  on  manufacturing  buildings, 
but  are  suitable  for  factory  offices  or  wherever  a  paneled  roof 
effect  is  desired.  They  are  made  of  either  tin  or  terne  plate  or 
of  painted  sheet  steel,  and  have  the  usual  merits  of  metal  roofs, 
being  light  and  not  easily  broken.  They  are  made  in  a  great 
variety  of  styles  and  patterns,  many  of  which  present  a  very 
attractive  appearance.  They  can  be  laid  only  on  pitch  roofs,  and 
weigh  from  90  to  110  pounds  per  square,  not  including  roof 
sheathing. 

Per  square. 

Charcoal  tin  shingles,  10X14  ins.,  painted,  cost $  6.50 

Sheet  steel  shingles,  10X14  ins.,  lead  coated,  cost 9.75 

Thorn's  I.  C.  charcoal  shingles  (tin),  cost $  8.50  to     9.75 

Thorn's  sheet  steel  shingles,  lead  coated,  cost 10.75  to  13.75 

TIN  AND  TERNE  PLATE  ROOFS. 

The  material  known  as  tin  plate  is  light  iron  or  steel,  coated 
on  the  surface  with  tin.  The  old  and  better  method  of  tin  coating 
was  to  submerge  the  sheets  in  a  tin  solution  until  the  surface  of 
the  steel  was  thoroughly  coated.  In  the  newer  method,  the  sheets, 
after  being  coated,  are  passed  between  adjustable  rollers  which 
regulate  the  thickness  of  the  coating.  The  finished  sheets  look 
alike,  but  those  having  the  thickest  coating  are  the  most  durable 
and  the  most  expensive.  Charcoal  iron  and  Bessemer  steel  are 
both  used,  but  the  former  is  preferred. 


290  MILL  BUILDINGS 

Terne  plates  are  similar  products  coated  with  lead  or  a  com- 
bination of  tin  and  lead  instead  of  tin,  and  they  are  the  kind 
most  used,  though  they  are  less  durable  and  cheaper  than  tin 
plate.  If  the  roof  must  be  walked  upon,  some  other  kind  of 
covering  is  preferable  to  tin,  for  travel  is  likely  to  break  the 
soldered  joints.  It  is  best  suited  for  flat  or  small  pitch  roofs,  on 
which  workmen  can  stand  while  soldering  and  making  the  seams. 

Both  tin  and  terne  plates  are  made  in  three  standard  sizes, 
10  X  14,  14  X  20  and  28  X  20  inches;  the  larger  ones,  requiring 
fewer  seams,  are  the  least  expensive  and  best  suited  for  factory 
buildings.  The  three  grades  are  marked  1C,  IX,  XX,  correspond- 
ing to  Nos.  30,  28  and  26  gages,  respectively.  Tin  and  terne  plates 
are  sold  in  boxes  containing  112  sheets  in  each  box.  The  weight 
of  a  box  of  14  X  20-inch  sheets  is  107  pounds  for  1C  tin  plate  and 
135  for  IX  plate,  and  twice  these  weights  for  sheets  20  X  28 
inches. 

With  flat  seam,  a  box  of  14X20  in.  sheets  covers 192  sq.  ft. 

With  flat  seam,  a  box  of  28X20  in.  sheets  covers 339  sq.  ft. 

With  standing  seam,  a  box  of  14X20  in.  sheets  covers 169  sq.  ft. 

With  standing  seam,  a  box  of  28X20  in.  sheets  covers 370  sq.  ft. 

Tin  and  terne  plate  roofing  weighs  from  62  to  75  pounds  per 
square  when  laid,  depending  on  the  quality  and  size  of  sheet 
used.  These  plates  are  laid  over  sheathing  on  roofs  of  any  pitch. 
On  flat  slopes  the  joints  must  all  be  soldered,  but  on  steeper  ones 
soldering  is  needed  on  the  cross  joints  only,  the  sides  being  folded. 
It  is  fastened  to  the  roof  by  sheet  metal  clips  which  are  soldered 
or  folded  in  the  joints,  the  outer  end  of  clips  being  nailed  to  the 
roof,  and  the  exposed  surface  has  no  perforations.  For  long 
sloping  roofs,  the  cross  joints  may  be  made  at  the  shop  and  strips 
delivered  at  the  building  in  rolls  of  the  proper  length  to  reach 
from  ridge  to  eave.  The  roofing  should  be  laid  on  felt  or  asbestos 
paper  to  reduce  the  noise  and  prevent  condensation.  All  joints 
must  be  locked  and  soldered  on  roofs  that  are  flat  or  nearly  so. 
Smaller  sheets  are  preferable  for  flat  roofs  that  are  subject  to 
occasional  travel,  because  the  greater  number  of  seams  increases 
the  strength  of  the  covering  and  prevents  it  from  buckling  or 
sagging.  Valleys,  gutters  and  downspouts  should  be  made  of 
IX  grade,  which  is  thicker  and  more  durable  than  1C,  though  the 
1C  grade  is  best  suited  for  roofing  sheets  requiring  sharp  bends 
for  the  standing  seams. 


SHEET  METAL  EOOFING  291 

Two  good  roofers  will  lay  from  1-J  to  3  squares  per  day  of  8 
hours. 

Sheets  should  be  painted  on  the  under  side  before  laying,  and 
the  upper  exposed  surface  soon  after  completion,  one  gallon  of 
paint  being  required  for  400  square  feet  of  surface.  Paint  will 
adhere  better  to  the  metal  if  it  remains  unpainted  for  a  month  or 
two,  so  the  rain  will  wash  the  surface.  Benzine  and  gasoline  are 
effective  in  removing  grease,  when  paint  must  be  applied  imme- 
diately. Tin  roofs  should  be  painted  every  two  years,  and  when 
well  laid  with  good  plates  and  soldered  joints,  should  last  from 
30  to  40  years. 

Tin  and  terne  plate  roofing  costs  from  $7  to  $12  per  square, 
depending  on  the  location  and  the  grade  of  tin  plate.  When  made 
of  small  sheets,  the  cost  is  about  25  per  cent  greater  than  from 
large  ones,  on  account  of  the  greater  number  of  seams.  Soldered 
joints  cost  50  cents  per  square  more  than  standing  seams. 

STANDARD  SPECIFICATIONS  FOR  TIN"  ROOFING 

ADOPTED  BY  THE  NATIONAL  ASSOCIATION 

OF  SHEET  METAL  WORKERS. 

Roof  Incline,  (a)  If  flat-seam,  the  roof  shall  have  an  incline 
of  J  inch  or  more  to  the  foot. 

(b)  If  standing-seam,  it  shall  have  an  incline  of  not  less  than 
2  inches  to  the  foot. 

(c)  Gutters,   valleys,  etc.,   shall  be  designed  with   sufficient 
incline  to  prevent  water  standing  in  them  or  backing  up  far  enough 
to  reach  the  standing  seams. 

Sheathing  Boards.  These  shall  be  of  good,  well  seasoned  dry 
lumber,  narrow  widths  preferred,  free  from  holes  and  of  even 
thickness.  Boards  shall  be  laid  with  tight  joints,  or  tongued 
and  grooved  with  nail  heads  well  driven  in.  Green  hemlock,  chest- 
nut, oak  and  ash  are  not  recommended. 

Sheathing  Paper.  Not  necessary  where  the  sheathing  boards 
are  laid  as  specified  above,  but  if  used,  it  shall  be  waterproof.  No 
tar  paper  or  others  containing  acids  are  allowed.  No  nails  shall 
be  driven  through  the  sheets. 

Flat  Seam.  If  the  sheets  are  laid  singly,  the  size  shall  be 
14  X  20.  The  sheets  shall  be  fastened  to  the  sheathing  boards  by 
cleats,  using  three  to  each  sheet,  two  on  the  long  and  one  on  the 
short  side.  There  shall  be  two  1-inch  barbed  wire  nails  to  each 


292  MILL  BUILDINGS 

cleat,  no  nails  to  be  driven  through  the  sheets.  If  put  on  in  rolls, 
the  sheets  shall  be  made  up  into  long  lengths  in  the  shop,  the 
cross  seams  locked  together  and  well  soaked  with  the  solder.  The 
rolls  shall  be  applied  the  narrow  way,  fastened  to  the  roof  with 
cleats  spaced  8  inches  apart,  cleats  locked  into  the  seam  and 
fastened  to  the  roof  with  two  1-inch  barbed  wire  nails  to  each 
cleat. 

Standing  Seam.  The  sheets  shall  be  put  together  in  long 
lengths  in  the  shop,  the  cross  seams  locked  together  and  well 
soaked  with  solder.  All  standing-seam  roofing  shall  be  applied 
the  narrow  way,  fastened  with  cleats  spaced  one  foot  apart.  One 
edge  of  the  course  shall  be  turned  up  1-J  inches  at  a  right  angle, 
when  the  cleats  shall  be  installed.  The  next  course  shall  have  the 
adjoining  edges  turned  up  1-|  inches.  These  edges  shall  be  locked 
together,  and  the  seams  so  formed  shall  be  flattened  to  a  rounded 
edge. 

Valleys  and  Gutters.  These  shall  be  of  IX  tin  and  formed 
with  flat  seams,  using  sheets  the  narrow  way. 

Flashings.  Wherever  practicable,  flashing  shall  be  let  into 
the  joints  of  the  brick  or  stone  work  and  cemented.  If  counter- 
flashings  are  used,  the  lower  edge  of  the  counter  part  shall  be 
kept  at  least  three  inches  above  the  roof. 

All  solder  used  on  the  roof  shall  be  of  the  best  grade,  bearing 
the  manufacturer's  name,  and  guaranteed  one-half  tin  and  one-half 
lead,  using  nothing  but  rosin  as  a  flux,  and  well  sweated  into  all 
searns  and  joints. 

Painting.  All  painting  shall  be  done  by  the  roofer.  Before 
laying,  all  tin  shall  be  painted  one  coat  on  the  under  side.  The 
upper  surface  of  the  tin  roof  to  be  carefully  cleaned  of  all  rosin, 
dirt,  etc.,  and  immediately  painted.  Paint  to  be  of  pure  metallic 
brown  iron  oxide,  or  Venetian  red  as  a  pigment,  mixed  with  pure 
linseed  oil.  No  patent  driers  or  turpentine  to  be  used.  All  coats 
of  paint  to  be  applied  with  a  hand  brush  and  well  rubbed  on. 
Apply  a  second  coat  two  weeks  after  the  first,  and  a  third  coat 
one  year  later. 

General  Instructions.  Xo  substitution  of  a  cheaper  grade  of 
tin  will  be  allowed.  The  object  of  these  specifications  is  to  pro- 
vide tin  roofs  of  the  same  durable,  satisfactory  nature  as  those 
generally  obtained  in  former  years  by  the  use  of  high-grade  mate- 
rial and  thorough,  first-class  workmanship.  The  roofer  is  expected 
to  do  good  work,  and  only  a  first-class  job  of  roofing  will  be 
accepted. 


SHEET  METAL  ROOFING  293 

No  unnecessary  walking  over  the  tin  roof,  or  using  the  same 
for  storage  of  materials,  shall  be  allowed  at  any  time.  It  is  rec- 
ommended that  workmen  wear  rubber  shoes  when  on  the  roof. 
Wherever  possible,  tin  shall  be  laid  with  standing  seam,  which 
allows  for  expansion  and  contraction. 

To  keep  the  roof  in  good  condition,  subsequent  painting  will 
hardly  be  necessary  at  shorter  intervals  than  three  to  five  years, 
or  even  longer,  depending  upon  local  conditions. 

Since  gutters  are  the  natural  receptacles  for  dirt,  leaves,  etc., 
they  should  be  swept  out  and  painted  every  two  or  three  years. 


CHAPTER  XXVII. 

CORNICES  AND  FLASHING. 

Metal  cornices  are  always  made  to  special  order,  and  exact 
measurements  for  making  them  must,  therefore,  be  given,  for  they 
cannot  be  exchanged  if  made  wrong.  They  are  suitable  as  a  finish 
for  the  main  eaves  or  on  the  eaves  of  monitors,  but  they  should  be 
plain,  or  nearly  so,  without  ornamentation  such  as  modillions  or 
dentils.  A  few  cornice  designs  are  shown  in  Fig.  461. 


Fig.  461. 


The  cost  of  cornices  is  estimated  by  the  superficial  square  foot, 
which  depends  directly  on  their  perimeter.  The  perimeter  or 
girth  of  that  part  of  the  cornice  outside  of  the  wall  surface  is 
equal  to  H  +  2  P  where  P  is  the  cornice  projection  and  H  the 
height,  as  shown  in  Fig.  462.  Any  part  of  the  cornice  toward  the 
left  of  the  building  face  must  be  added  to  the  length  of  the 
perimeter  as  given  by  the  formula.  No.  24  galvanized  iron  plain 
cornices  cost  from  10  to  12  cents  per  square  foot  in  place.  Cor- 
nices made  of  No.  16  ounce  copper  cost  30  to  35  cents  per  square 
foot.  Ornamental  shapes  with  modillions  and  dentils  might  cost 
twice  these  amounts. 

Some  forms  of  ventilator  cornices  are  shown  with  the  venti- 
lator detail  in  Figs.  576  to  585. 

GABLE   COENICES. 

These  should  be  made  to  correspond  in  a  general  way  with  the 
eaves.  Some  common  forms  are  shown  in  Figs.  463  to  466.  Fig. 
463  was  used  on  a  large  forge  shop  in  New  England,  designed  by 
the  writer  in  the  year  1908,  but  the  effect  is  clumsy  and  not  so 
neat  as  a  molded  cornice,  which  costs  no  more. 

294 


COENICES  AND  FLASHING 


295 


Fig.   462. 


Fig.  463. 


Fig.  464. 


J 


Fig.  465. 


Fig.  466. 


Fig.  467. 


Fig.  468. 


Fig.  469. 


Fig.  470. 


Fig.  471. 


296 


MILL  BUILDINGS 
METAL    FLASHINGS. 


Metal  flashing  details  can  be  shown  better  than  described.  It 
is  important  that  hips,  valleys,  chimney  openings  and  wall  joints 
be  tight,  for  if  not,  a  roof  which  might  otherwise  be  first  class 
may  be  rendered  useless.  Flashing  should  be  with  sheet  steel  or 
copper,  for  iron  will  crack  in  making  sharp  bends. 

RIDGE   ROLLS. 

These  are  made  in  a  great  variety  of  patterns,  many  of  which 
are  quite  ornamental,  but  the  ornamental  ones  are  better  suited  to 
steel  market  or  other  buildings  with  architectural  features  (Figs. 
30  and  34)  than  for  ordinary  mills.  A  few  plain  ridge  details 
are  shown  in  Figs.  467  to  470,  the  roll  at  the  crown  giving  a 
finished  appearance.  For  use  over  corrugated  iron,  either  the 
aprons  of  the  capping  must  be  corrugated  or  wood  fillers  must  be 
fitted  into  the  roofing  beneath  the  ridge  cap.  The  wood  fillers  are 
supplied  by  the  corrugated  iron  makers  and  cost  2  cents  per  lineal 
foot,  and  galvanized  ridge  rolls  cost  from  5  to  10  cents  per  foot 
for  plain  designs  as  shown,  or  10  to  20  cents  per  foot  for  orna- 
mental ones.  They  should  be  at  least  No.  24  gage. 


HIP  AND  VALLEY  FLASHING. 

Hips  are  covered  with  regular  ridge  rolls  over  special  wood  fill- 
ing pieces  in  the  corrugations,  and  are  nailed  through  the  cap 
and  sheathing,  and  fastened  either  to  the  steel  ridge  rafter  or  to 
a  beveled  wood  capping  piece  over  it  (Fig.  471). 

Valleys  are  flashed  with  wide  sheets  of  flat  metal,  using  either 
a  heavy  galvanized  steel,  IX  terne  plate  or  copper.  Valleys  require 


Fig.  472. 


Fig.  473. 


Fig.  474. 


CORNICES  AND  FLASHING 


297 


more  careful  attention  than  ridges,  on  account  of  the  greater 
amount  of  water  in  them.  The  flashing  should  be  carried  well 
up  under  the  sheathing  and  riveted  thereto,  the  vertical  distance 
from  bottom  of  valley  to  edge  of  flashing  being  not  less  than  8 
inches  (Fig.  472). 

COENEE   CAPPING. 

Details  of  corner  capping  for  buildings  are  shown  in  Fig.  473. 
They  are  used  either  inside  or  outside  of  the  building  to  cover  the 
corner  corrugated  iron  joints,  and  the  edges  of  the  capping  are 
rolled  as  shown,  so  no  sharp  or  ragged  metal  edges  will  appear. 
Each  angle  of  the  capping  is  6  inches  wide  and  is  fastened  to  the 
siding  with  rivets  6  inches  apart. 

Figs.  474,  475  and  476  show  other  forms  of  corner  capping, 
the  first  having  grooves  to  receive  and  cover  the  edges  of  the 
siding  sheets,  and  the  last  is  similar  to  ordinary  ridge  rolls.  Their 
application  is  more  fully  shown  in  Fig.  477. 


Fig.   475. 


Fig.   47G. 


Fig.  477. 


CHIMNEY  AND  WALL  FLASHING. 

Around  brick  chimneys,  flashing  is  laid  under  the  roofing  and 
turned  up  against  the  chimney,  the  edge  being  hammered  into 
brick  joints  and  cemented.  Against  gable  or  fire  walls  parallel 
to  the  corrugations,  iron  roofs  are  flashed  with  sheets  of  metal 
(Fig.  478).  Flashing  for  walls  standing  normal  to  the  corruga- 
tion is  shown  in  Fig.  479. 


Fig.  478. 


Fig.  479. 


298 


MILL  BUILDINGS 


DOOK    AND    WINDOW    CASING. 

Figs.  480,  481  and  482  show  metal  casings  for  wood  window 
and  door  frames,  which  are  best  when  formed  at  the  shop  and 
shipped  ready  for  placing.  Some  builders  prefer  to  send  this 
metal  to  the  building  in  flat  sheets  and  bend  it  there  to  fit  the 
windows,  but  the  result  is  never  so  neat  as  when  bends  are  made 
by  machines  at  the  metal  shop.  The  work  done  by  hand  tools  at 
the  site  invariably  shows  irregularities  that  greatly  injure  the 
appearance.  The  three  views  show  window  jambs,  caps  and  sills. 


Fig.  480. 


Fig.  481. 


Fig.  482. 


CHAPTER  XXVIII. 

GUTTERS  AND  DOWNSPOUTS. 

GUTTEES. 

Gutters  for  mill  buildings  are  made  in  several  forms,  some  of 
which  are  here  described  and  illustrated.  Those  at  the  eaves  may 
be  either  hanging,  box  wall,  roof  or  combination  gutters,  and  valley 
gutters  are  also  made  in  several  ways. 

TABLE  LI. 

SIZE   OF  EAVE   GUTTERS. 

Use  5-in.  eave  gutters  for  roof  slopes  up  to  20  ft. 
Use  6-in.  eave  gutters  for  roof  slopes  up  to  40  ft. 
Use  7-in.  eave  gutters  for  roof  slopes  up  to  60  ft. 
Use  8-in.  eave  gutters  for  roof  slopes  up  to  80  ft. 

The  above  are  roof  slopes  or  half  the  span  of  double  pitch 
roofs.  A  small  gutter  with  a  large  slope  will  keep  itself  clean 
and  free  from  sediment,  when  larger  but  flatter  ones  will  become 
clogged. 

Gutters  are  usually  made  of  galvanized  steel,  though  charcoal 
iron  at  a  slightly  higher  price  is  more  durable.  Nos.  27  or  28 
gage,  which  is  commonly  used  on  residences,  is  too  thin,  and  no 
metal  less  than  24  gage  is  recommended  for  manufacturing  build- 
ings. Copper  gutters  are  more  durable,  but  are  not  as  much 
used  on  mills  because  of  their  higher  cost. 

The  slope  of  gutters  is  generally  made  one  inch  in  10  feet,  but 
it  must  never  be  less  than  one  inch  in  15  feet,  for  water  would 
not  have  sufficient  flow  to  keep  the  gutters  clean.  When  condi- 
tions will  permit,  a  slope  of  one  inch  in  5  feet  is  preferable,  but 
this  amount  may  not  always  be  available. 

Galvanized  iron  gutters  erected  in  place  cost  about  2  cents 
for  each  inch  of  girth  per  lineal  foot  of  gutter;  therefore,  an 
8-inch  girth  costs  16  cents  per  foot,  and  a  10-inch,  20  cents.  The 
price  of  the  usual  size  galvanized  iron  gutters  varies  from  15  to 
35  cents  per  lineal  foot,  complete.  Copper  gutters,  16  ounces, 
cost  15  cents  per  square  foot  for  the  material  and  35  cents  per 
square  foot  erected  in  place. 

299 


300 


MILL  BUILDINGS 


r 


4'0" 


Fig.  483. 


Main  Column.'  _ 

Section  through  Eaves. 

Fig.  484. 


Fig.  485. 


Fig.  486. 


Fig.   487, 


f      Fig.   488. 


Fig.  489. 


Fig.  490. 


GUT  TEES  AND  DOWNSPOUTS 
HANGING  GUTTERS. 


301 


These  gutters  are  made  in  10-foot  lengths  and  shipped  in 
crates  containing  25  pieces  in  each  crate.  Unless  otherwise 
ordered,  they  are  made  with  slip  joints,  as  this  kind  requires  no 
soldering,  are  more  easily  erected,  and  are  not  affected  by  con- 
traction and  expansion.  Lap  joints  cost  -J  cent  per  foot  less  than 
slip  joints,  but  are  not  as  satisfactory.  Fig.  489  shows  the  stand- 
ard makes  of  hanging  gutters,  with  both  single  and  double  bead. 

TABLE  LIT. 


APPROXIMATE  PRICES  FOR  HANGING  GUTTERS,  NOT  ERECTED 

3  -in.  trough,  galvanized  steel  or  charcoal  iron,  costs     4  cents 
3%-in.  trough,  galvanized  steel  or  charcoal  iron,  costs 

4  -in.  trough,  galvanized  steel  or  charcoal  iron,  costs 
41/£-in.  trough,  galvanized  steel  or  charcoal  iron,  costs 

5  -in.  trough,  galvanized  steel  or  charcoal  iron,  costs 

6  -in.  trough,  galvanized  steel  or  charcoal  iron,  costs 

7  -in.  trough,  galvanized  steel  or  charcoal  iron,  costs 


per  ft. 
per  ft. 
per  ft. 
per  ft. 
per  ft. 
per  ft. 
per  ft. 
8  -in.  trough,  galvanized  steel  or  charcoal  iron,  costs  10  cents  per  ft. 


4  cents 

5  cents 

5  cents 

6  cents 

7  cents 

8  cents 


These  prices  are  J  cent  per  lineal  foot  for  every  inch  of  girth. 
Standard  inside  and  outside  miter  pieces  for  both  slip  and  lap 
joints  are  kept  in  stock  by  the  makers,  ready  for  placing. 

GUTTER  SUPPORTS. 

Several  methods  of  supporting  hanging  gutters  are  shown  on 
page  302.  Figs.  491  and  492  show  malleable  cast  iron  brackets, 
fastened  to  the  eaves  with  adjustable  circular  supports,  which 
may  be  raised  or  lowered  to  suit  the  gutter  slope.  The  brackets 


*Fig.   491. 


Fig.  492. 


From  Eller  Mfg.  Co. 


302 


MILL  BUILDINGS 


are  fastened  to  the  eave  with  bolts  or  nails  or  they  may  be  driven 
into  the  wood  facings.     This  kind  of  bracket  costs 

$5  to  $6  per  100  for    5-inch  gutter. 

6  to     7  per  100  for    7-inch  gutter. 

7  to    9  per  100  for  10-inch  gutter. 

Fig.  493  shows  steel  bar  hangers  with 
adjustments  to  regulate  the  gutter  slope. 
The  suspension  bars  are  nailed  or  bolted 
to  the  roof  and  the  cross  bars  grip  the 
side  of  the  gutters.  They  cost  about 
$1.50  per  gross. 

Galvanized  wire  eave  trough  hangers 
(Fig.  494)  are  easily  applied  and  cost 
from  $2  to  $3  per  gross. 


Fig.  493. 


Figs.  495  and  496*  show  two  forms  of  hanging  gutter  at  the 


Fig.  494. 


Adjustable    Strap 
Hangers 


Fig.  495. 


Adjustable       Hanging       Gutter. 
Fig.   496. 


Mill  Building  Construction,  H.  G.  Tyrrell,  1900. 


GUTTERS  AND  DOWNSPOUTS 


eave  of  a  building  covered  with  corrugated  iron.     Supports 
hanging  gutters  must  be  spaced  not  over  4  feet  apart. 


303 

for 


BOX  GUTTEES. 

Several  forms  of  box  gutters  are  shown  in  Fig.  497,  and  one 
at  the  eave  of  a  mill  building  with  brick  walls  (Fig.  498*).  They 
cost  generally  from  10  to  20  cents  per  lineal  foot,  and  double  this 
amount  in  place. 

Oufer  Edge  af  Cutter  mus+-be  beneath 
Roof  Plane  prolonged.  Purlin  punched 
with  j£  Holes  fo  take  Hangers, 
for  Hanging   Gutter. 


Fig.  497. 


of  Iron.  Gutters. 
Fig.   498. 


KOOF   GUTTEES. 


These  are  made  of  galvanized  steel  in  two  shapes  (Figs.  499 
and  500),  and  come  in  8  and  10  foot  lengths.  The  hangers  are 
placed  so  as  to  leave  no  nail  or  screw  heads  exposed.  They  cost 
from  8  to  15  cents  per  lineal  foot. 


Fig.   499. 


Fig.  500. 


304 


MILL  BUILDINGS 
COMBINATION   KOOF   GUTTERS. 


These  gutters  serve  the  double  purpose  of  gutter  and  cornice 
and  they  require  no  hangers  or  braces.  They  are  made  in  two  sec- 
tions, the  upper  one  being  sloped  (Fig.  501)  to  give  the  proper 
grade.  The  first  illustration  shows  the  parts  separated  and  the 
second  one  the  two  parts  in  position. 


Fig.   501. 


VALLEY   GUTTEES. 

Fig.  502*  shows  designs  for  single  and  double  valley  gutters, 
especially  suitable  for  mill  buildings.  The  lining  is  supported 
by  a  series  of  bent  angle  bars,  spaced  3  to  4  feet  apart  and  fastened 
to  the  roof  purlins,  the  dimension  "a"  varying  with  each  support 
to  suit  the  grade  of  gutter.  The  horizontal  bottom  width  of  gut- 
ter is  therefore  greater  at  the  high  end  than  at  the  low.  The 


f  j?  Layers  Terr  Paper 
\\Z    »  Asbestos  » 


Detail  of  _Gutter 


with 


Purlins 


Fig.  502. 


Detail  of 
Valley  Gutter. 


GUT  TEES  AND  DOWNSPOUTS 


305 


gutter  is  lined  first  with  sheets  of  corrugated  iron,  to  give  the 
bottom  stiffness,  and  these  are  covered  with  heavy  flat  galvanized 
sheets,  passing  up  under  the  roofing  to  the  next  purlin.  With  the 
dimensions  shown  on  drawing,  water  must  be  8  inches  deep  in 
the  gutter  before  it  would  leak  through  into  the  building.  Half 

gutters  adjoining  walls  are  flashed  up 
against  the  brick  work  with  flashing 
driven  into  the  brick  joints  and  ce- 
mented. When  carefully  built,  the  val- 
ley gutters  give  excellent  satisfaction. 
They  cost  complete,  including  the 
double  lining  and  supports,  about  10 
cents  per  superficial  foot. 

A  suspension  valley  gutter  made  of 
No.  20  flat  galvanized  steel  is  shown  in 
Fig.  503.  The  slope  is  easily  adjusted 
and  the  gutter  is  less  expensive  than  the  one  last  described,  but  it  is 
not  as  rigid,  and  may  be  injured  in  cleaning  it. 

DOWNSPOUTS. 

Wherever  ice  forms,  downspouts  should  be  corrugated,  for 
they  can  then  freeze  up  without  bursting.  In  warm  climates, 
where  ice  never  forms,  smooth  downspouts  may  be  preferable.  Gal- 
vanized steel  downspouts  are  made  in  10-foot  lengths,  and  copper 
spouts  in  8-foot  lengths,  and  they  are  shipped  in  crates  containing 
twenty-five  pieces  in  each.  Galvanized  metal  should  be  not  less 
than  No.  24  gage. 


Fig.  503. 


Fig.  504. 


306 


MILL  BUILDINGS 


The  general  rule  for  the  size  of  downspouts  is  to  provide  one 
square  inch  of  pipe  for  100  square  feet  of  roof  surface.  In  island 
climates  or  along  the  coast,  where  rainfall  is  often  excessive,  the 
area  of  spouts  may  be  increased  25  per  cent. 


TABLE  LIII. 

SIZE  OF  GUTTERS  AND  DOV7NSPOUTS. 

One-half  roof  span 10     20     30     40     50  60     70     80 

Size  of  gutter  in  in 5       5*6       6       7  7       8       8 

Size  of  downspout  in  in 3       3       4       4       5  5       6       6 

Spacing  of  downspout  in  ft 50     50     50     50     40  40     40     40 

3  -inch  downspout  will  serve  1,000  square  feet  of  roof  surface. 


TABLE  LIV. 
COST  OF  NO.  24  GALVANIZED  STEEL  CORRUGATED  DOWNSPOUTS. 


Size. 
2-in.. 
3-in. 
4-in. 
5-in. 
6-in. 


Cost  delivered. 

Cents  per  ft. 

6 

7 


9 
10 


Cost  erected. 
Cents  per  ft. 

10 

15 

20 

25 

30 


Fig.  505. 


Fig.  506. 


Fig.  507. 


Fig.  508. 


Fig.  509. 


Fig.  510. 


GUTTERS  AND  DOWNSPOUTS  307 

The  erected  prices  include  fitting,  freight,  cartage  and  erec- 
tion labor,  and  are  approximate  only. 

Copper  spouts  are  more  durable,  but  not  generally  used  on 
account  of  their  higher  cost.  Copper,  16  ounce,  costs,  for  the 
material  only,  15  cents  per  pound,  and  spouts  erected  in  place 
cost  30  to  35  cents  per  pound. 


TABLE  LV. 

COST    OF    16-OUNCE    COPPEE   DOWNSPOUTS. 

2     X3  in 40  cents  per  ft.       3^X5  in 65  cents  per  ft. 

2  X4  in 50  cents  per  ft.       4     X5  in 70  cents  per  ft. 

3  X4  in 55  cents  per  ft.       4     X6  in 75  cents  per  ft. 


CHAPTER  XXIX. 

VENTILATORS. 

The  subject  of  ventilation  is  discussed  in  Chapter  IX  and  only 
the  details  will  be  treated  here.  Change  of  air  in  a  building  is 
secured  by  one  of  the  following  methods: 

(1)  Forced  drafts  through  ducts  from  blowers*. 

(2)  Monitor  ventilators,  such  as  windows,  shutters  or  louvres. 

(3)  Movable  windows  in  saw-tooth  roofs. 

(4)  Continuous  side  openings  in  plane  of  roofs. 

(5)  Individual  metal  ventilators. 

(6)  Box  skylight  openings. 

(7)  Wall  ventilation. 

The  first  method,  by  means  of  forced  air  currents,  is  discussed 
in  connection  with  heating  systems  and  saw-tooth  window  ventila- 
tion is  fully  explained  in  Chapter  XVII. 

Roof  and  wall  openings  are  explained  and  illustrated  in  Chap- 
ter IX.  Continuous  openings  beneath  the  eave,  covered  with 
|-inch  screen  wire  mesh,  are  shown  in  the  illustration  for  tropical 
market  buildings  (Figs.  30  and  34),  and  the  continuous  side 
openings  admit  a  free  flow  of  fresh  air,  which  passes  out  at  the 
roof  monitors. 

Box  skylight  ventilators  are  illustrated  in  Chapter  XXXI,  on 
skylights.  The  only  methods  that  will  be  included  here  are,  there- 
fore, individual  ventilators  and  monitor  ventilation  through  win- 
dows, shutters  or  louvres. 

INDIVIDUAL  METAL  VENTILATOES. 

Natural  air  currents  to  some  extent  are  induced  by  placing 
metal  ventilators,  preferably  at  the  ridge  or  highest  point,  to 
draw  off  the  foul  and  heated  air  which  rises  and  collects  under 
the  roof.  These  are  self-acting,  with  no  expense  for  oper- 
ating. They  are  made  of  galvanized  sheet  iron  or  copper  and 
in  a  variety  of  styles.  They  must  have  dampers  or  regulators,  so 
air  circulation  can  be  checked  or  stopped  when  desired,  and  their 
construction  should  be  such  that  back  draft  into  the  building  is 
impossible.  The  dampers  should  be  easily  operated  without  noise, 

308 


VENTILATOES 


309 


and  so  made  that  they  cannot  be  clogged  with  snow  or  ice.  The 
most  approved  styles  have  dampers  made  of  a  sliding  or  tele- 
scoping sleeve,  operated  by  a  cord  and  pulley  and  closed  by  being 
drawn  up  against  the  cover.  The  ventilator  tops  are  either  sheet 
metal  or  wire  glass  tightly  set  into  the  metal  siding,  thus  form- 
ing a  combination  ventilator  and  skylight.  The  latter  are  prefer- 
able, for  they  not  only  admit  extra  light  but  permit  the  interior 
of  the  metal  tube  to  be  inspected,  and  always  show  whether  it  is 
open  or  closed. 

The  best  makes  of  ventilators  with  glass  tops  have  drips  or 
gutters  under  the  edge  of  the  glass  and  inside  around  the 
bottom.  The  glass  must,  however,  be  tightly  set  so  no  water 
from  outside  can  leak  through.  When  glass  tops  are  used,  a  slid- 
ing or  telescoping  damper  is  better  than  a  revolving  pipe  damper, 
for  the  latter,  when  closed,  obscures  the  skylight. 

The  following  table  gives  dimensions,  weight  and  cost  of  gal- 
vanized iron  ventilators  from  12  to  72  inches  in  diameter,  the 
costs  being  for  the  best  makes.  Cheaper  ones  can  be  bought  for 
one-half  the  prices  given,  while  copper  will  cost  twice  as  much: 


B 


/9 

«--£-_, 

Fig.  511. 


TABLE  LVI. 
DIMENSIONS,  WEIGHT  AND  COST  OF  GALVANIZED  IRON  VEN- 


A. 

12 
14 
16 
18 
20 
24 
30 
36 
42 
48 
54 
60 
66 
72 


B. 


C. 


17 

20 

21 

23 

24 

26 

26 

30 

29 

33 

34 

40 

43 

50 

52 

60 

60 

70 

69 

80 

77 

90 

86 

100 

94 

110 

104 

120 

TILATORS. 

Area. 

113 

153 

200 

254 

314 

452 

706 
1,017 
1,386 
1,809 
2,390 
2,827 
3.456 
4,071 


Price, 

Weight. 

Gage. 

Galv.  Iron. 

19 

22 

$  5.00 

22 

22 

.      7.50 

26 

22 

10.00 

31 

22 

12.50 

37 

20 

15.00 

50 

20 

18.00 

100 

20 

25.00 

145 

18 

37.00 

200 

18 

54.00 

330 

18 

62.00 

390 

16 

75.00 

470 

16 

80.00 

550 

16 

90.00 

625 

14 

100.00 

310 


MILL  BUILDINGS 


Some  of  the  best  makes  of  circular  metal  ventilators  have 
fusible  links  in  the  cords  which  hold  them  open,  and  in  case  of 
fire  they  close  automatically  and  stop  all  draft.  Metal  ventilators 
are  suitable  for  use  on  saw-tooth  roofs  with  fixed  windows,  and 
on  boiler  houses  or  shops  which  are  excessively  warm  (Figs.  512 
to  519). 


Fig.  512. 


Fig.  513. 


Fig.  514. 


Fig.  515. 


Fig.  516. 


Fig.  517. 


VENTILATORS  311 

LOUVEES. 

Louvres  are  bent  sheets  of  metal  fastened  into  frames,  the 
sheets  lapping  over  each  other  enough  to  exclude  snow  and  rain. 
They  are  occasionally  used  on  the  sides  or  ends  of  buildings,  but 
oftener  on  monitors^  where  a  large  amount  of  continuous  ventila- 
tion is  needed.  They  are  made  both  fixed  and  movable,  but  the 
latter  forms  are  rarely  used,  as  movable  shutters  are  preferred. 
Movable  louvres  (Figs.  520  and  521),  on  account  of  their  light 
weight,  are  easily  rattled  by  the  wind,  and  as  they  cost  more  than 
steel  shutters,  they  have  no  advantage  over  them.  Louvres  are 
best  suited  to  buildings  such  as  rolling  mills,  forge  shops,  or 
wherever  smoke  and  gas  is  found,  requiring  permanent  openings  in 
the  roof  for  their  removal.  They  must  be  firmly  held  in  place,  so 
the  wind  will  not  cause  them  to  rattle,  tear  them  loose,  or  close 
the  openings,  rendering  them  useless. 


Fig.  518.  Fig.  519. 

The  thickness  of  metal  should  not  be  less  than  No.  22  gage 
for  black  or  painted  iron  or  No.  24  gage  for  galvanized,  and  the 
distance  longitudinally  between  supports  must  be  proportioned  to 
the  strength  of  the  louvre  sheets. 

The  required  area  of  open  space  in  the  louvre  frame  can  be 
determined  by  making  the  area  of  opening  per  100  square  feet  of 
floor  surface  according  to  the  following  table:  As  buildings 
increase  in  height,  they  are  more  easily  ventilated  and  require  a 
proportionally  smaller  area  of  roof  ventilation: 


312 


MILL  BUILDINGS 


TABLE  LVII. 

REQUIRED  AREA  OF  LOUVRE  OPENINGS  IN  SQ.  FT.  PER  100  SQ. 
FT.  OF  FLOOR  SURFACE,  FOR  VARIOUS  BUILDING  HEIGHTS. 


Mills     

Forge  shops 


Height  in  ft.  to  eave. 

20  30  40 

12  10  8 

14  12  10 


50 
6 
9 


The  above  areas  are  60  per  cent  more  than  needed  in  openings 
where  the  air  currents  are  unobstructed  by  the  louvre  slats. 

Some  common  forms  of  louvres  are  shown  in  Figs.  520  to  524. 
Fig.  522*  is  a  very  neat  form  made  of  No.  24  galvanized  sheets, 


Louvre  Slots 


Fig.  520. 


Fig.  521. 


11  inches  wide,  with  edges  rolled.  They  require  supports  not 
greater  than  49  inches  apart,  and  as  the  ends  are  lapped  from  J 
to  ^  inch,  the  greatest  sheet  lengths  are  4  feet  1-J  inches.  The 
slats  are  fastened  through  T5g-inch  holes  to  angle  uprights  by  J-inch 
screw  head  bolts,  f  inch  long,  and  they  are  separated  by  louvre 
blocks  If  inches  long  by  each  vertical  support,  which  prevents 
them  from  closing  under  wind  pressure.  The  design  is  defective 


Mill  Building  Construction,  H.  G.  Tyrrell.     1900. 


VENTILATOES 


313 


in  having  no  bolts  or  ties  to  prevent  interior  wind  pressure  from 
spreading  the  metal  slats  and  causing  them  to  rattle.  The  illus- 
tration shows  the  detail  for  louvres  adjoining  both  corrugated  iron 
siding  and  wood  window  sash. 

Fig.  523  shows  another  design  for  continuous  louvres  which 
are  made  in  10-foot  lengths.  The  slats  are  made  with  straight 
bends  without  curves  and  they  are  tied  together  with  bolts,  and 


Corn  Iron  ffivefe-' 
Fig.  522. 


rackets 
af  Splices 


t'fex'/d  Brackets 

at  Splices 


Fig.  523. 


Fig.   524 


314 


MILL  BUILDINGS 


separated  by  short  sections  of  pipes.  The  lower  section  is  bolted 
to  the  uprights  and  rests  on  the  side  roof,  while  the  upper  one  is 
molded  in  the  form  of  a  cornice  and  fastened  to  the  roof  purlin. 
Fig.  524  shows  another  set  of  louvres,  which  are  held  out  from 
the  vertical  by  braces  at  the  top  and  bottom  and  united  on  the 
outer  face  by  1J  X  -g-inch  straps  at  the  joints.  They  are  made  of 
No.  22  gage  metal  in  maximum  length  of  7  feet.  The  lower  louvre 
slat  is  set  not  less  than  6  inches  above  the  adjoining  roof,  so  the 
opening  will  be  effective.  Fixed  galvanized  iron  louvres  cost  com- 
plete in  place  about  40  cents  per  square  foot. 

Corr.  Iron -Roof 


^^^    \EndFlatIron 


•Stan'd  Vent  Flashing     . 
Purlins  should  be  /oca  ted 
in  Position  to  fit  Bevel  of 
Standard  Ventilator  Flashlr> 


r 

.0/1.    j                   „      n    in                     "^ 

r> 

V 

* 

•                                                          ' 

•1 

\ 

K\ 

• 

t^£    2"  less  than              * 

& 

\ 

sx  jg   'Length  cf  'Shutter     -( 

'     x 

\ 

[ 

^ 

^ 

>     _ 

r_ 

Fig.   525. 
SHUTTERS. 

Ventilator  shutters  (Fig.  525*)  in  monitor  sides  may  be  made 
of  flat  or  corrugated  iron,  Nos.  12  to  14  gage  being  suitable  for 
flat  plate  shutters  and  No.  22  for  corrugated,  but  in  either  case 
it  is  preferable  to  have  the  sheet  galvanized.  When  the  shutters 
are  galvanized,  all  flashing,  bolts,  clips,  clinch  nails,  or  other 
fastening,  any  part  of  which  shows  on  the  exterior,  must  also  be 
galvanized. 

The  shutters  are  made  in  a  uniform  width  of  30  inches  and 
lengths  varying  from  5  to  10  feet,  and  are  stiffened  with  a  light 
border  frame  of  1-|  X  iVinch  angles  with  intermediate  cross  angles 
2  to  3  feet  apart.  Fig.  525  shows  the  framing  for  a  standard  angle 
shutter  8  feet  long.  They  are  suspended  from  the  upper  monitor 
purlins,  using  two  hinges  for  lengths  of  7  feet  or  under  and  three 


VENTILATORS  315 

hinges  for  greater  lengths,  and  are  held  in  closed  position  with 
brass  springs,  as  shown,  one  spring  serving  the  two  opposite  shut- 
ters. They  are  opened  by  a  T%-inch  wire  rope  attached  to  a  light 
angle  iron  lever  fastened  to  the  center  of  each  shutter,  and  are 
held  open  by  hooking  the  wire  rope  under  some  of  the  roof  fram- 
ing, or  by  attaching  it  to  a  wall  cleat  near  the  floor.  Shutters 
hinged  at  the  top  are  less  liable  to  leak  than  trunnioned  shutters, 
though  the  latter,  on  account  of  being  balanced,  are  easier  to 
operate.  The  hinged  shutters,  as  shown,  lap  at  the  ends  and  bot- 
tom over  the  framing,  and  are  waterproofed  at  the  top  by  wide 
projecting  flashing  which  serves  also  as  a  monitor  cornice. 


CHAPTER  XXX. 

GLASS. 

There  are  three  kinds  of  glass  in  general  use  for  lighting, 
known  as  sheet  glass,  plate  glass,  and  prisms,  the  last  being  very 
little  used  for  factory  buildings,  on  account  of  its  high  cost. 

Sheet  glass  is  made  in  single  and  double  strength,  with  thick- 
nesses of  iV  and  -J  inch,  respectively,  and  is  suitable  for  use  where 
liability  to  breakage  is  small,  in  sizes  up  to  about  6  square  feet. 
It  is  made  in  three  grades,  known  as  AA,  A  and  B,  the  AA  being 


ROUGH. 


RIBBED    WIRE. 


ROUGH     WIRE. 


Fig.  526. 


RIBBED. 


the  best  and  B  the  poorest  quality.     A  and  B  qualities  are  the 
kinds  generally  used  for  manufacturing  buildings. 

Plate  glass  is  made  in  thicknesses  from  T3¥  to  j  inch,  and 
should  be  used  for  skylights  and  large  window  panes,  or  wherever 
thinner  glass  is  unsuitable. 

316 


GLASS  317 

TABLE  LVIII. 
WEIGHT  PER  SQ.  FT.  OF  PLATE  GLASS. 

%  in.  thick,  weighs  2  Ibs.  per  sq.  ft. 

•&  in.  thick,  weighs  21/£  Ibs.  per  sq.  ft. 

*4  in.  thick,  weighs  3%  Ibs.  per  sq.  ft. 

%  in.  thick,  weighs  5  Ibs.  per  sq.  ft. 

%  in.  thick,  weighs  7  Ibs.  per  sq.  ft. 

%  in.  thick,  weighs  8%  Ibs.  per  sq.  ft. 

%  in.  thick,  weighs  10  Ibs.  per  sq.  ft. 

The  best  thickness  of  plate  glass  for  different  sizes  is  as 
follows : 

12X  48  or  15X40  inches &  in.  thick 

15X   60 ^4  in.  thick 

20X100    %  in.  thick 

Many  skylight  makers,  however,  use  J-inch  thick  plate  glass 
for  widths  of  20  to  24  inches,  and  find  it  satisfactory. 

Plate  glass  is  made  either  plain  or  reinforced  with  wire,  and 
the  surface  is  either  polished,  rough,  ribbed,  or  maize  (Fig.  526). 
Wire  glass  is  preferable  for  skylights,  for  if  the  glass  is  broken 
the  imbedded  wire  netting  holds  the  glass  together  and  prevents 
its  falling.  It  is  also  valuable  for  retarding  fire,  for  while  plain 
glass  breaks  with  heat  and  leaves  draft  openings  in  the  walls  or 
roof,  the  wire  glass,  even  when  broken,  remains  in  position.  Wire 
glass  costs  more,  and  is  20  per  cent  less  effective  for  lighting  than 
plain  glass,  but  a  greater  area  overcomes  the  latter  objection, 
while  the  extra  cost  is  a  small  item  in  an  entire  building. 

Rough  and  ribbed  plate  wire  glass  (Fig.  526)  are  the  kinds 
best  suited  for  factory  use,  and  particularly  for  skylights.  Light 
is  not  so  well  diffused  through  rough  plate  as  through  ribbed 
glass,  but  rough  plate  is  preferred  by  many  because  it  is  easier  to 
clean.  The  ribs  of  fluted  glass  become  clogged  with  dust  and  soot, 
and  unless  it  is  thoroughly  and  frequently  washed,  the  dust  will 
obscure  more  light  than  a  roughened  surface.  The  ribs  should 
be  placed  on  the  inside  or  outside  of  the  building,  according  as 
one  or  the  other  is  more  accessible  for  cleaning,  and  the  ribs 
should  be  vertical  on  side  windows,  and  parallel  with  the  roof 
slopes  on  skylights;  but  for  double  glazing  the  ribs  should  face 
each  other  and  be  crossed.  Factory  glass  has  twenty-one  ribs  per 
lineal  inch.  Careful  experiments  show  that  ribbed  glass  diffuses 
light  better  than  any  other  kind,  but  as  there  is  no  benefit  from 
ribbing  both  sides,  one  side  is  made  smooth.  The  best  method  of 
glazing  side  windows  is  to  use  ribbed  glass  in  the  upper  sash,  and 
plain  double-strength  sheet  glass  in  the  lower  ones.  The  new  shops 
of  the  Sturtevant  Company  are  glazed  in  this  way. 


318  MILL  BUILDINGS 

Double  glazing  causes  a  great  saving  of  heat  in  winter  seasons 
and  is  extensively  used  in  northern  latitudes.  The  Fiberoid  plant 
at  Springfield,  Massachusetts,  has  double  glazed  windows,  and  the 
Great  Northern  Eailway  shops  at  St.  Paul  have  double  glazed  sky- 
lights, with  J-inch  ribbed  plate  glass  above,  and  double-strength 
sheet  glass  below,  with  wire  netting  underneath.  A  saw-tooth 
roof  built  for  the  Farr  Alpaca  Company  at  Holyoke,  Massachu- 
setts, has  double  glazed  sash  on  the  roof,  with  ^-inch  ribbed  glass 
inside  and  double-strength  sheet  glass  outside. 

COST  OF  GLASS. 

Price  lists  are  issued  by  the  glass  manufacturers,  which,  in 
1908,  were  subject  to  the  following  discounts : 

Sheet   glass    90  and  45% 

Polished  plate  glass  under   5   sq.    ft 75,  10  and     5% 

Polished  plate  glass  between  5  and  10  sq.  ft 80  and     5% 

Polished  plate  glass  over    10  sq.    ft 80  and  10% 

The  cost  of  sheet  and  polished  plate  glass  varies  with  the  size 
of  sheet,  but  is  approximately  as  follows : 

Double  strength  sheet  glass $  .06  to  $  .10  per  sq.  ft. 

Polished  plate  wire  glass,  either  side  over  40  in...  1.25  per  sq.  ft. 

Polished  plate  wire  glass,  either  side  24  to  40  in..  .90  per  sq.  ft. 

Polished  plate  wire  glass,  either  side  under   24  in.  .60  per  sq.  ft. 

The  cost  of  setting  sheet  glass  is  from  15  to  20  per  cent  of  the 
cost  of  the  glass,  or  from  1-J  to  1J  cents  per  square  foot.  The  cost 
of  setting  plate  glass  is  about  5  per  cent  of  its  cost. 

Eibbed  and  maize  glass  is  sold  at  a  uniform  square  foot  price, 
independent  of  the  size  of  the  sheets,  and  the  prices  are  as  follows : 

fs  plain   ribbed    glass 9  to  12  cents  per  sq.  ft. 

^  maize  glass    18  cents  per  sq.  ft. 

^4  ribbed  or  maize  wire  glass 21  cents  per  sq.  ft. 

The  cost  of  erecting  or  laying  skylight  glass  is  from  8  to  10 
cents  per  square  foot. 


CHAPTER  XXXI. 

SKYLIGHTS. 

Skylights  are  used  in  buildings,  the  widths  of  which  are  too 
great  to  receive  sufficient  light  from  the  sides,  and  are  generally 
needed  when  these  widths  exceed  50  to  60  feet.  Many  forms  of 
skylights  serve  the  double  purpose  of  lighting  and  ventilating, 
the  latter  feature  being  discussed  later  in  connection  with  the 
various  forms  or  makes. 

The  proportion  of  roof  which  should  be  covered  with  glass 
varies  from  25  to  50  per  cent,  depending  on  the  use  of  the  build- 
ing and  other  conditions  which  are  explained  in  Chapter  IX.  A 
building  for  rough  work  or  storage  will  not  need  as  much  light 
as  a  machine  shop  or  mill  where  fine  work  with  much  detail  is  car- 
ried on. 

The  common  forms  of  skylights  are  as  follows,  each  form 
being  described  separately: 

(1)  Glass  Skylights  in  Plane  of  Eoof. 

(2)  Individual  Box  Skylights. 

(3)  Glass  Tile. 

(4)  Prisms. 

(5)  Translucent  Fabric  in  Plane  of  Roof. 

Skylight  glass  is  held  in  position  and  made  water-tight  in  two 
general  ways : 

(1)  By  being  laid  in  putty  or  cement. 

(2)  By  the  use  of  felt  packing  in  the  joints,  compressed  with 
springs  and  bolts. 

As  glass  sheets  are  seldom  absolutely  flat,  laying  them  in  putty 
or  cement  prevents  the  sheet  from  breaking  and  at  the  same  time 
closes  all  openings  and  makes  the  roof  water-tight,  but  the  method 
has  the  disadvantage  of  causing  the  putty  to  grip  the  glass,  and 
vibration  in  the  building  from  the  movement  of  cranes  or  machin- 
ery often  results  in  broken  skylights.  Vibration  sometimes  causes 
the  putty  and  cement  to  break  and  fall  out,  leaving  larger  open- 
ings for  leakage  than  if  no  putty  or  cement  were  used.  To  obviate 
this  difficulty,  other  methods  have  been  devised  for  holding  the 

319 


320 


MILL  BUILDINGS 


glass  by  laying  it  on  strips  of  felt  or  packing  instead  of  in  cement 
or  putty,  while  still  other  methods  are  used  by  which  the  glass  is 
placed  between  metal  surfaces  and  leakage  through  the  joints  is 
carried  off  in  gutters.  In  any  case,  the  safety  of  workmen 
demands  either  the  use  of  wire  glass  or  a  strong  wire  mesh 
stretched  below  plain  glass  to  catch  falling  pieces  in  case  of 
breakage. 

On  box  skylights,  or  wherever  conditions  will  permit,  the  roof 
should  have  a  slope  of  8  inches  per  foot  or  one-third  pitch,  and 
even  on  flat  skylights  should  never  be  less  than  2  inches  per  foot. 

Section  of  End  Curb 
d ]Jro\i 


Copper  Gutter 
GJffss 
Skylight  Bar 


Puffy 
Copper  Cap 
Brass  Bolt 


Ridge  Connection 
Copper  upper  Lap 
Copper  Lower  Curb 
%*$*&*  L.Clip 
Rivet 

Iron  Cross  Boer 
Bar  Lug 


Fig.  527. 


One-third  pitch  is  the  common  practice.  On  roofs  which  have  a 
comparatively  flat  pitch,  it  assists  greatly  in  making  the  skylights 
water-tight  to  place  them  at  the  ridge  and  give  them  a  greater 
pitch  than  the  rest  of  the  roof,  as  shown  in  Figs.  26  and  107. 

BAES. 

Skylight  bars  are  made  of  rolled  steel,  cast  iron,  galvanized 
sheet  steel,  copper  and  wood.  The  essential  features  are  the 
flange,  gutters  and  caps,  and  they  differ  chiefly  in  these  particu- 
lars. Cast  iron  is  not  much  used,  as  the  rolled  steel  bars  are 


SKYLIGHTS 


321 


"Galv.  Iron  or 
Copper 


stronger  and  cost  no  more,  and  wood  bars  cannot  be  used  on  fire- 
proof buildings.  Their  use  is  restricted  largely  to  small  green- 
houses and  conservatories,  or  to  temporary  non-fireproof  buildings. 
The  kind  of  skylight  bars  suitable  for  fireproof  factory  buildings 
are,  therefore,  rolled  steel  or  sheet  metal,  either  galvanized  or 
copper.  Sheet  metal  has  the  advantage  of  being  light  and  cheap, 
and  forms  a  more  elastic  bed  for  the  glass  than  rolled  steel  bars, 
but  it  is  not  so  strong  or  durable.  Many  sheet  metal  bars  are 
formed  by  folding  a  single  sheet  into  the  desired  shape,  so  the 
finished  bar  has  only  a  single  joint. 

Figs.  527  to  554  show  skylight  bars  and  details,  for  both 
rolled  steel  and  sheet  metal,  with  or  without  putty. 

Fig.  527  shows  details  of  a  skylight  with  rolled  steel  bars  and 
glass  laid  in  putty.  The  bars  are  made  of  No.  10  to  No.  14  gage 
metal,  and  the  upper  caps  are  copper  or  galvanized  iron,  fastened 

with  brass  bolts  and  nuts.  Expansion 
is  provided  between  the  adjoining  bars, 
which  can  be  used  for  spans  up  to  12 
feet  without  intermediate  support.  The 
illustration  shows  the  application  of 
the  skylight  to  both  ridge  and  side  roof 
construction. 

Fig.  528  shows  a  very  simple  form 
of  skylight  bar  made  from  a  vertical 
rolled  steel  bar  with  a  cast  iron  gutter 
tap-screwed  to  the  lower  side.  The 
glass  is  laid  in  putty  and  the  ridge  is 

covered  with  a  cap  of  galvanized  iron  or  copper.  The  size  of  the 
vertical  bar  is  made  to  suit  the  length  of  span,  and  when  this 
length  is  too  great  for  a  single  length  of  glass,  the  sheets  of  glass 
are  then  overlapped,  and  the  thickness  of  iron  fillers  made  to 
correspond. 

Fig.  529  shows  the  Anti-Pluvius  skylight  made  by  the  G. 
Drouve  Company.  It  consists  of  a  series  of  rolled  steel  bars  to 
support  the  glass,  spaced  about  20  inches  apart,  and  strong  enough 
for  spans  up  to  8  feet.  For  lengths  greater  than  8  feet,  inter- 
mediate purlins  are  needed.  Stirrup  irons  are  screwed  into  the 
main  bars,  16  to  20  inches  apart,  with  their  tops  at  the  proper 
elevation  to  support  the  glass.  On  these  stirrups  is  laid  a  1|X  -J- 
inch  iron  plate,  and  the  glass  is  cushioned  between  strips  of  felt 
held  in  place  by  sheet  metal  guides  and  compressed  with  springs 
over  brass  stud  bolts  in  the  stirrups.  Over  the  joints  is  an 


Glass  ^ 


Iron  Filler - 


Cost  Iron  -- 

Fig.   528. 


322 


MILL  BUILDINGS 


inverted  bridge  bar,  on  which  to  walk.  When  sheets  of  glass  over- 
lap, the  stirrups  are  then  placed  at  different  elevations  for  the 
upper  and  lower  sheets.  There  is  no  contact  between  the  glass 
and  the  iron  bars,  and  therefore  no  condensation  on  them. 

Fig.  530  shows  the  Lupton  bar,  which,  on  account  of  its  shape, 
has  a  high  bending  strength;    the  glass  is  lapped  and  bars  and 


Curb  Flashing 
lobe  furnished 
byttenofer 


Curb  flashing  to  be 
'furnished  bg  roofer. 


Finish  of  Lower  Curb. 
Fig.   529. 


caps  are  offset  to  match.  The  swivel  stud  holds  the  cap  properly 
in  alignment,  while  saturated  oakum  is  placed  between  glass  and 
metal,  and  prevents  the  glass  coming  in  contact  with  the  main  bar 


SKYLIGHTS 


323 


and  forming  condensation.     The  joints  are  covered  with  a  copper 
cap  held  in  place  with  brass  nuts. 

Figs.  531  and  535  show  the  Van  Noorden  steel  skylight.  The 
channel  bars  are  bolted  to  the  roof  purlins  through  lugs  which 
have  depressions  in  the  side  at  intervals  of  18  inches  to  form 
seats  for  spring  clips,  through  which  brass  bolts  are  passed  which- 
hold  the  galvanized  iron  or  copper  caps  tightly  on  the  glass. 
The  absence  of  putty  in  forms  of  this  kind  allows  the  glass  to 
move  slightly  without  breaking,  during  the  operation  of  heavy 

cranes  and  machinery  which  cause 
vibration  in  the  entire  building. 
Some  skylight  bars  of  this  form 
have  frequent  perforations  in  the 
sides  of  the  bar  and  the  cap,  so  they 
act  both  as  skylight  and  ventilator. 
Figs.  532,  533  and  534  are 
other  forms  of  Van  Noorden  Com-' 
pany's  bars,  in  which  the  glass  is 

supported  without  being  in  contact  with  the  main  bars,  and  are 
therefore  less  liable  to  condensation  than  those  shown  in  Fig.  531. 
Fig.  536  shows  the  steel  skylight  bar  of  the  American  Machin- 
ery Company.  It  is  a  simple  anchor  shape,  varying  in  depth  from 
1J  to  6  inches,  with  glass  bedded  between  strips  of  felt.  The 
6-inch  one  is  strong  enough  for  spans  up  to  15  feet. 


Fig.  530. 


Fig.  531. 


Fig.   532. 


Fig.  537  shows  a  very  simple  form  of  putty  less  steel  skylight 
rib,  which  was  used  by  the  author  on  several  mill  buildings.  It 
can  be  made  in  any  structural  shop  from  common  shapes.  The 
upper  and  lower  members  are  1J  by  1-J  by  -f$  steel  angles,  the 
glass  being  bedded  between  strips  of  felt.  The  lower  angles, 


324 


MILL  BUILDINGS 


Fig.   533. 


Fig.   534. 


Fig.  535. 


Brass  Stud- 


Fig.  536. 


Fig.  537. 


-  Brass  Bolt 
TUNut 


Fig.  538. 


SKYLIGHTS 


325 


which  serve  as  glass  supports  and  gutters,  rest  in  small  castings 
on  the  purlins,  and  the  upper  angles  are  bolted  through  similar 
castings  on  the  ridge. 


,  Asbestos 

Cushion 


Fig.   539. 


Fig.   540. 


Fig.   541. 


Fig.  538  is  made  by  the  National  Skylight  and  Ventilator 
Company,,  and  used  without  putty,  the  glass  being  held  on  the  steel 
bar  with  nuts  screwed  down  on  the  spring  caps.  The  bolts  are 
fastened  to  the  steel  bars  by  being  dovetailed  into  them. 

Fig.  539  is  the  puttyless  skylight  bar  of  the  National  Venti- 


Fig.  542. 


lating  Company.  In  addition  to  the  features  shown  in  previous 
ones,  it  has  asbestos  cushions  beneath  the  glass  and  outside  sheet 
metal  condensation  gutters. 

Figs.  540  and  541  are  two  forms  of  sheet  metal  bars  with 
glass  laid  in  putty,  the  latter  having  a  flat  steel  center.  The 
bar  as  shown  in  Fig.  541,  when  made  of  No.  24  galvanized 
iron,  is  strong  enough  for  spans  up  to  8  feet,  and  when  of  No.  18 


326 


MILL  BUILDINGS 


galvanized  iron,  is  strong  enough  for  spans  from  10  to  12  feet. 
The  system  is  shown  in  perspective  in  Fig.  542. 

Fig.  543  shows  the  puttyless  sheet  metal  ventilating  bar  of 
the  Lyster  Sheet  Metal  Company.  It  is  similar  to  those  last 
described  excepting  that  there  are  numerous  openings  in  the  side 
and  cap,  and  it  acts  as  skylight  and  ventilator  at  the  same  time. 


Fig.  543. 


Fig.  544. 


Figs.  544  and  545  show  the  Vaile  and  Young  puttyless  sheet 
metal  skylight  bar  for  short  and  long  spans  respectively,  the  light 
one  being  strong  enough  for  spans  up  to  8  feet. 

Fig.  546  shows  skylights  with  bars  and  framing  made  of  wood, 
and  is  suitable  only  for  temporary  or  non-fireproof  buildings. 

COST  OF  FLAT  SKYLIGHTS. 

The  cost  of  flat  skylights  depends  chiefly  on  the  length  of 
spans  and  corresponding  weight  of  bars,  and  varies  generally 


Fig.  545. 


Fig.  546. 


from  40  to  60  cents  per  square  foot,  including  all  material  in 
place. 

Large  skylights  with  steel  channels  and  copper  caps  weigh  8 
pounds  per  square  foot  and  cost  from  50  to  60  cents  per  square 
foot  erected.  When  bars  and  caps  are  made  of  galvanized  iron, 


SKYLIGHTS  327 

the  cost  will  not  exceed  30  to  40  cents  per  square  foot  in  place. 
The  cost  of  erecting  skylights  is  8  to  10  cents  per  square  foot. 

BOX   SKYLIGHTS. 

Box  or  individual  skylights  are  made  in  small  areas  and 
placed  on  curbs  standing  at  least  6  inches  above  the  plane  of  the 
roof.  They  are  made  in  several  forms  with  single  and  double 
pitch,  as  shown  in  Figs.  547  to  552.  The  standard  slope  used  on 
box  skylights  is  8  inches  rise  per  foot  or  J  pitch.  A  double  pitch 
box  skylight  12  feet  wide  would  therefor^  have  a  rise  of  4  feet. 
The  curbs  are  raised  above  the  roof  level  for  the  purpose  of 
flashing  them  and  preventing  slush  and  snow  from  leaking  in, 
and  their  tops  are  generally  level. 


Fig.  547. 

When  it  is  desired  to  combine  ventilating  with  lighting,  the 
skylights  are  placed  on  high  curbs  which  have  movable  sash  or 
louvres  in  the  side;  or  one  or  more  glass  panels  on  the  top  may 
be  hinged,  though  the  latter  method  is  liable  to  cause  leakage. 
Side  ventilator  windows  may  be  opened  or  closed  in  sets,  with 
mechanism  similar  to  the  device  used  for  monitor  windows  de- 
scribed in  Chapter  XXXIII.  High  box  skylights  should  have 
eave  gutters  and  spouts  at  the  corners  so  water  will  not  run  down 
on  the  sash  or  louvres.  Wire  glass  is  preferable  to  plain  glass, 
but  when  plain  is  used  a  wire  netting  must  be  placed  beneath  it. 

The  Pennsylvania  Eailway  Locomotive  shop  at  Wilmington, 
Delaware,  has  roof  skylights  as  shown  in  Fig.  553.  They  are 
not  continuous  and  are  placed  only  between  the  trusses  and  not 
over  them. 

The  hipped  turret  skylight  with  ridge  ventilator,  movable 
side  sash  and  locking  apparatus  (Fig.  548)  costs  from  $1.25  per 


328 


MILL  BUILDINGS 


Fig.  548. 


Fig.  549. 


Fig.  550. 


Fig.  551. 


Fig.  552. 


SKYLIGHTS 


329 


horizontal  square  foot  for  8  X  14-ft.   size,  to  $2   per  horizontal 
square  foot  for  4  X  6-ft.  skylight. 

The  hipped  turret  skylight  with  stationary  louvre  ventilators 
in  the  sides  (Fig.  549)  costs  from  80  cents  per  horizontal  square 
foot  for  8  X  14  ft.  size,  increasing  to  $1.25  for  3  X  5  ft. 


ru— -or 

Fig.  553. 


Composition*1  Roofing 


/£' 'Plank. 


j        ( 2%"Spikincf  Piece 


Fig.   554. 


Double  pitched  turret  skylights  without  side  ventilators  (Fig. 
550)  cost  from  40  cents  per  horizontal  square  foot  for  7  X  12  ft. 
to  65  cents  per  horizontal  square  foot  for  2X3  ft. 


330  MILL  BUILDINGS 

Double  pitch  box  skylights  (Fig.  551)  cost  from  35  cents  per 
horizontal  square  foot  for  large  sizes  to  75  cents  for  small  ones. 

Single  pitch  box  skylights  (Fig.  552)  cost  25  cents  per  hori- 
zontal square  foot  for  8  X  12-foot  size,  increasing  to  40  cents  for 
minimum  size. 

The  above  costs  for  box  skylights  are  based  in  all  cases  on  the 
use  of  galvanized  sheet  metal  bars. 

TILE  SKYLIGHTS. 

Several  tile  manufacturers  make  glass  tiles  similar  to  opaque 
ones  (Fig.  432).  The  glass  tiles  cost  from  50  to  60  cents  each, 
and  they  may  be  either  scattered  over  the  roof,  alternating  with 
opaque  ones,  or  they  may  be  assembled  in  blocks  or  strips  similar 
to  ordinary  glass  skylights.  They  produce  an  attractive  appear- 
ance, but  are  too  expensive  for  common  factory  use. 

Prism  lights  may  also  be  occasionally  used  on  manufacturing 
buildings  in  crowded  city  districts,  where  direct  sunlight  is  pre- 
vented by  adjoining  buildings,  but  their  use  is  too  limited  to  merit 
further  description  here. 

•TRANSLUCENT  FABRIC. 

This  is  a  flexible  substitute  for  glass  skylight  made  of  a  light 
wire  mesh  imbedded  in  a  thin  oil  composition,  only  thick  enough 
to  cover  the  wire.  The  wire  mesh  is  made  of  No.  26  gage,  and 
the  mesh  has  12  openings  per  lineal  inch.  The  composition  is 
amber  colored,  and  it  admits  a  large  proportion  of  light  well 
diffused.  Its  chief  merit  is  its  flexibility,  for  it  can  be  used  on 
steel  frame  buildings  where  glass  skylights  would  be  broken.  The 
action  of  jib  and  shop  traveling  cranes,  steam  hammers  or  other 
heavy  machinery  causes  the  framing  of  steel  buildings  to  spring 
so  much  that  glass  skylights  are  frequently  broken,  and  not  only 
incur  expense  for  replacing  them  but  cause  leaks ;  and  falling 
skylights  are  a  danger  to  the  workmen.  The  fabric  will  not  take 
fire  unless  exposed  to  excessive  heat,  and  then  the  oil  composition 
burns  with  profuse  black  smoke.  All  things  considered,  it  is 
probably  as  satisfactory  as  glass.  In  hot  weather  the  composition 
softens  somewhat  and  collects  soot  and  dirt,  and  it  must,  therefore, 
be  frequently  cleaned.  It  is  made  in  sheets  3  feet  3  inches  wide, 
6  feet  3  inches  or  7  feet  3  inches  long,  and  the  strips  are  laid 
lengthwise  of  the  roof,  the  horizontal  seams  lapped  2  inches.  It  is 
fastened  with  1^-inch  (3d)  nails,  using  1^  pounds  per  hundred 
feet  of  seam. 


SKYLIGHTS 


331 


Fig.  555*  shows  a  method  used  by  the  author  for  laying  trans- 
lucent fabric  on  the  roof  of  a  monitor,  and  the  material  was  first 
used  on  a  forge  shop  in  the  East,  designed  by  him  in  1897.  A 
light  wood  frame  was  placed  over  the  angle  purlin  with  wood 
rafters  6  feet  apart  and  nailing  pieces  bolted  to  the  purlins.  The 


S  ' 

r--2x4"  Wood  bolted  to  Pur/in 
wi-rh  z'x  1'B.H.  Bolt  about 
2*  6"  apart 

i 
« 

tiv_-E 

i  ^. 

Continuous  6alv.  Wire  No.  10, 
&7  Ibs.  per  100  -ft. 

^3"  Wood 

^  %k 
i~.jd 

Continuous  Wire 
^4"  Wood 

^..^..  .._.„ f.  r/J  '' . ....  _  , _,T_  o 

^   Dimensions    for   Lockioint 


Ik 


Lap  Joint.    Capped  Joint.  Lock  Joint.    Methods  for  Fasten inq 

Wire  Ends.        * 


Dimensions  given  are  for 

LeckJa'nf 


sheets  were  laid  lengthwise  of  the  building  and  overlapped  2 
inches,  at  the  center  longitudinal  purlin.  The  shop  had  12-foot 
truss  panels,  and  the  fabric  sheets  were,  therefore,  made  6  feet  3 
inches  long,  allowing  3  inches  for  the  joints.  Two  lines  of  No.  10 
galvanized  wire  were  stretched  midway  between  the  longitudinal 
*  Mill  Building  Construction.  H.  G.  Tyrrell.  1900. 


332  MILL  BUILDINGS 

purlins,  and  fastened  at  the  ends  to  prevent  the  cloth  from  sag- 
ging. Joints  at  right  angles  to  the  eave  were  locked,  and  the 
ridge  was  covered  with  metal  ridge  capping.  At  the  eave  was 
placed  a  neat  galvanized  iron  cornice  with  an  outer  drip  carried 
up  on  the  roof  under  the  fabric  and  nailed  to  the  wood  purlin 
cap.  It  is  now  manufactured  by  the  P.  J.  Ferguson  Company, 
Norfolk  Downs,  Quincy,  Massachusetts,  and  costs  10  cents  per 
square  foot,  f.  o.  b.  factory,  or  22  cents  per  square  foot  with  nails 
and  wire,  erected  in  place,  but  not  including  the  cost  of  frame- 
work. It  has  since  been  used  on  the  Tennessee  Centennial  Exposi- 
tion Building  at  Nashville,  and  on  many  of  the  buildings  for  the 
Trans-Mississippi  Exposition  at  Omaha  in  1898.  A  building  for 
the  Atchison,  Topeka  and  Santa  Fe  Eailroad  at  Topeka,  155x850 
feet,  has  translucent  fabric  skylights  at  the  ridge,  and  the  General 
Electric  machine  shop  at  Schenectady,  built  in  1904,  has  40  per 
cent  of  the  roof  thus  covered. 


CHAPTER  XXXII. 

WINDOWS. 

* 

SIDE  WALL  WINDOWS. 

The  windows  in  mill  buildings  may  be  supported  by  wood  or 
steel  studs  or  purlins  covered  with  sheathing,  or  they  may  be  built 
into  walls  of  solid  stone,  brick  or  concrete.  Sometimes  window 
frames  are  set  on  a  solid  base  wall,  built  up  to  the  level  of  the 
window  sills,  and  supporting  a  framed  wall  above  them.  The 
details  of  frames  and  windows  depend  largely  upon  the  nature  of 
the  walls. 


Fig.   556. 

WOODEN    SASH. 

The  proper  dimensions  for  sash  of  different  sizes  are  as  fol- 
lows :  Sash  5X6  feet  and  larger  should  be  2  inches  thick,  have 
-J-inch  mullion,  with  3-inch  stiles  and  top  rails,  and  5-inch  bot- 
tom rail ;  sash  4X4  feet  to  5  X  6  feet  should  be  If  inches  thick, 
have  f-inch  mullions,  2^ -inch  stiles  and  top  rail,  and  4-inch  bottom 
rails ;  and  those  smaller  than  4X4  feet  should  be  1J  inches  thick, 
have  J-inch  mullion,  2-inch  stiles  and  top  rail,  and  3-inch  bottom 
rail. 

The  following  table  gives  the  dimensions  of  ordinary  single 
window  sash : 

333 


334 


MILL  BUILDINGS 


a>COCMCMOCDCOCOCD 
T— I 

^       r^       ib       *b       *b      CD  -    co       t-       t~- 

3       ^         X        j*!         H        vX        vX 


>-        QO        O5 
XXX 


00          Oi          O5          rH          CM 

X         X         X         X         X 


£^        OO        00 

co      co 


00  00  Tt< 

co       co       ^ 


00          00 
CO          CO 


s  < 

<1   ^ 

^  3 

w 


c^ 


fH       » 

IS 

la 

*^ 


c, 

^ 

^   co 

00    CM 

^    ^ 

CO 

00 

CM 

^ 

^ 

CO 

GO 

b 

S: 

0 

i    i 

CM    CM 

i     fc 

CM    O 

5H    X 
O    CM 

X 
i 
CM 

v^ 
CM 

vx 
b 

vX 

b 

X 

5: 

CM 

X 
i: 

CM 

•s. 

CJ 

CM         CM         CM 


COiOt^CiCMOOT-HlOOOCM'HHOOCOt^rH 
rHTHrHrHCM'-ICMCMCMCOCMCMcOCOTtl 


S 


CO         CM          CM 


CO    CO    CO 


to   CD   co 


•<^    IO    IO    IO    CO    CO    t~ 


00    O5    00    Oi    OS    rH    CM 


rH          rH  rH         rH  rH          rH 

CMCMCOCOCOCMCMCOCOCOCMCMCOCOCO 


O     » 


CO         00         CM 


fc          5          £  i          fc          5          S 

CO          OO          CM          TjH          ^f          CO          OO 


CM         CM         CM 


|.SP 

§r^l 


00          OO          GO          00          OO 


CM          CM         CM         CM         CM 


WINDOWS 


335 


When  clearance  will  permit,  sash  may  be  strengthened  by 
extending  the  stiles  an  inch  or  two  above  and  below  the  top  and 
bottom  rails. 

The  best  sash  and  frames  are  made  of  white  pine,  and  without 
glass  or  paint,  1-f-inch  sash  posts  from  5  to  7  cents  per  square  foot, 
and  IJ-inch  from  7  to  12  cents  per  square  foot.  Glazing  with 
single  strength  glass  costs  from  6  to  8  cents  per  square^  foot,  or 


—  3  flashing  -  - . 

Fig.   557. 

8  to  10  cents  for  double  strength  glass.  The  above  prices  are  for 
sash  only,  without  frames,  f.  o.  b.  Chicago.  It  is  usual  to  esti- 
mate sash,  glazed,  painted  and  erected  in  place  at  25  cents  per 
square  foot. 

CONTINUOUS  SASH. 

A  design  for  a  foundry  made  by  the  author  (Fig.  21)  has 
10  feet  of  continuous  wood  sash  bolted  to  steel  purlins  (Fig.  556), 
and  other  details  for  sash  on  side  walls  are  shown  in  Figs.  557 
and  558. 

WOOD  WINDOW  FRAMES. 

A  detail  for  window  frame  and  casing,  supported  by  steel  pur- 
lins, is  shown  in  Fig.  559*.  The  outstanding  legs  of  the  steel 
window  angle  are  cut  away,  permitting  the  members  to  fit  closely 
over  the  steel  purlins  to  which  they  are  fastened  with  counter- 
sunk bolts.  The  wood  frame  and  casing  is  bolted  to  the  steel 

*  Mill  Building  Construction.     H.  G.  Tyrrell.     1900. 


336 


MILL  BUILDINGS 


I-  Corrugated  Steel 
—^ 1 TT^I 


n 


Corrugated  Steek 


Fig.  558. 


Corf, 


QI 


-Flashing 


"Block 


T—& 


Bot 


13 


Fig.  559. 


WINDOWS 


337 


\ 


II M 

I 


Plan  of^Stool 
Fig.   560. 


fl 


<'/t  5 'tops 


Fig.   561. 


-—Corrugated  Steel 


---Purlin 


Flashing 


Screw 


Fig.  562. 


338 


MILL  BUILDINGS 


through  TVinch  holes  about  one  foot  apart,  and  the  casing  may 
be  made  more  nearly  fireproof  by  being  covered  with  sheet  metal 
(Figs.  480,  481  and  482). 

Fig.  560  shows  details  for  vertical  trunnioned  sash  in  wood 
frames,  supported  by  steel  purlins.  The  window  frame  is  bolted 
to  the  steel  work  and  the  casing  may  be  covered  with  sheet  metal. 
Fig.  561  shows  a  mullion  wood  window  frame  for  corrugated 
iron  wall  with  sash  omitted. 

Figs.  562,  563  and  564  are  details  for  windows  in  steel  walls, 


i 


'Corrugated  Steel 


MS?%>?:::; 


^ 


^•Purlin 


•Purlin 


f  Lag  Screw 

JhicHness  of  Sash:  ity'when 
both  Dimensions  are  leas  f/iqp4-& 
1^4  when  either  exceeds  4-0 


Fig.  563. 


which  are  rolling,  counterbalanced,  and  double  hung,  respectively. 
Counterbalanced  windows  are  economical  on  account  of  having 
plain  frames  and  requiring  no  weights. 

Details  for  a  wood  window  frame  in  a  brick  wall  are  illus- 
trated in  Fig.  565. 

These  frames  usually  have  from  twenty-four  to  forty  lights  or 
panels,  and  the  size  of  wall  openings  for  windows  with  10  X  12- 
inch  glass  are  as  follows: 


NUMBEE  OF  LIGHTS. 


24 
28, 
32, 
40, 


4X7  ft.  0  in. 

4X8  ft.  1  in. 

4X9  ft.  1  in. 

4  ft.  10  in.  X  9  ft.  1  in. 


WINDOWS 


339 


-Corrugated  Steel 
-flashing 


Lag  5 crew 


Fig.   564. 


OmiHvdon  I 

Fig.  565. 


340  MILL  BUILDINGS 

Wood  window  frames  should  have  sills  and  pulley  stiles  from 
1J  to  If  inches  thick,  with  |-inch  parting  strips,  and  the  joints 
should  be  put  together  with  white  lead  paint.  The  sills  should 
be  grooved  on  the  under  side  to  form  a  drip. 

COST  OF  WOOD  FEAMES  AND  WINDOWS. 
In  estimating  windows,  it  is  convenient  to  use  prices  including 
all  details,  such  as  sash,  frames,  glass,  painting,  sills,  hardware 
and  setting.  Approximate  prices  for  common  size  windows  in 
place,  including  the  above  items  and  double  strength  glass,  with 
cost  of  paint,  are  as  follows : 

Windows  3X7  ft.  6  in.  in  brick  walls  cost $16.50 

Windows  3X7  ft.  6  in.  in  frame  walls  cost 12.50 

Windows  2  ft.  6  in.  X  6  ft.  6  in.  in  brick  walls  cost 14.50 

Windows  2  ft.  6  in.  X  6  ft.  6  in.  in  frame  walls  cost 10.00 

The  cost  of  setting  window  frames  is  usually  one-third  of  the 
cost  of  material. 

An  itemized  cost  estimate  for  a  plain  3  X  6-foot  wood  window 
without  casing,  in  brick  walls,  is  as  follows : 

Box    frame    $3.10 

20  sq   ft.  sash,  at  6  cents 1.20 

16  sq.  ft.  glass,  at  7  cents 1.12 

5  ft.  stone  sill,  at   60  cents    3.00 

5  ft.  stone  lintel,   at   40   cents 2.00 

Paint,  55  sq.  ft.,  at  2  cents 1.10 

Weights,  110  Ibs.,  at  1%  cents 1.38 

20  ft.  chain,  at  4  cents 80 

4  pulleys,  at  15  cents 60 

Lift  and  lock 50 

Erection    .  2.00 


.$16.80 

Box  window  frames  in  brick  walls  with  If-inch  sash  and 
double  strength  glass,  including  weights,  hardware,  paint  and  set- 
ting, together  with  stone  still  and  lintel,  cost  75  cents  per  square 
foot  of  brick  opening.  Similar  windows  in  frame  walls,  which 
require  no  stone  sill  or  lintel,  cost  50  cents  per  square  foot.  Win- 
dows with  plank  frames,  fixed  sash,  and  no  weights  or  hardware, 
will  cost  less. 

METAL  SASH   AND   WINDOWS. 

Sheet  metal  sash  and  frames  are  made  in  a  variety  of  ways,  a 
few  of  which  are  shown  in  Figs.  566  to  571.  Fig.  566  shows 
inside  and  outside  views  of  metal  windows  in  brick  walls  with 
single  trunnioned  sash,  while  Fig.  567  is  a  similar  window  with 
double  sash,  and  Fig.  568  is  a  mullion  window  in  concrete  walls 


WINDOWS 


341 


Fig.  566. 


zzizz—tiniJp' 


Fig.  567. 


342 


MILL  BUILDINGS 


with  double  trunnion  sash.    Figs.  569  and  571  are  views  of  double 
hung  metal  sash  in  metal  frames. 

With  iron  or  sheet  metal  frames  and  wire  glass,  steel  fire 
shutters  are  no  longer  necessary,  and  the  extra  cost  of  the  fire- 
proof windows  is  no  greater  than  the  combined  cost  of  wood  win- 
dows and  shutters.  Some  makers  of  sheet  metal  windows  use 
fusible  links  in  the  cord  which  holds  the  windows  open,  and  in 
case  of  fire  the  soft  fusible  metal  melts  and  allows  the  windows  to 


Fig.   568. 

close  from  their  own  weight.  The  device  is  an  excellent  one,  for 
it  closes  openings  which  would  cause  draft  and  add  impetus  to 
a  fire. 

Metal  windows  including  sash  and  frames  without  glass  cost 
55  cents  per  square  foot  with  double  hung  sash,  and  40  cents  per 
square  foot  with  trunnioned  sash.  Rough  plate  glass  costs  21 
cents  per  square  foot,  and  plate  wire  glass  95  cents,  while  setting 
glass  costs  5  cents  per  square  foot  more.  The  cost  of  complete 
metal  windows  will  therefore  be  the  combined  costs  of  metal  and 
glass,  as  given  above,  depending  on  the  kind  of  windows  and  glass 
selected. 


WINDOWS 


343 


The  Allis-Chalmers  pattern  shop  and  storage  building  at  West 
Allis,  Wisconsin,  has  wire  glass  in  iron  frames  and  is  a  typical 
example  of  fireproof  window  construction. 


Pig.  569. 


Fig.   571. 


STEEL   SASH. 


Window  sash  with  solid  rolled  steel  bars  are  coming  into  gen- 
eral use  for  manufacturing  buildings.  They  are  stronger  and 
more  durable  than  sheet  metal  sash  and  offer  greater  resistance 
to  fire. 

Fig.  572  shows  details  of  patent  steel  bars  made  by  the  Detroit 
Steel  Products  Company.  The  bars  are  soft  steel  and  vertical 
ones  are  split  at  the  point  where  muntins  cross,  and  the  horizontal 
muntins,  which  are  notched  at  intersection,  are  passed  through 
slots  in  the  vertical  ones,  and  the  expanded  web  of  vertical  mun- 


344 


MILL  BUILDINGS 


tins  is  driven  back  into  notches  in  the  horizontal  bars,  thus  hold- 
ing the  bars  together.  Glass  is  held  in  position  with  pins  through 
holes  drilled  in  the  webs  of  bars,  and  secured  further  with  putty. 
If  side  ventilation  is  desired,  the  sash  are  made  to  swing  on  side 


Fig.   572. 


Fig.  573. 

trunnions  (Fig.  573).  Steel  sash  cost  20  to  40  cents  per  square 
foot  at  the  factory,  not  including  glass,  and  about  3  cents  per 
square  foot  for  erection  in  large  quantities.  A  large  manufac- 
turing building  in  Ohio,  the  plans  of  which  were  prepared  in  1902, 
partly  by  the  writer,  had  steel  sash  made  on  1-inch  channels,  the 
glass  being  held  in  place  by  small  flats  and  angle  bars.  Other 
details  of  windows  and  doors  are  shown  in  Figs.  574  and  575. 


WINDOWS 


345 


'l\&- Door  Hanger  Section  throuqh 

i  Door  Jamb.3 


Section  through  Door  Transom. 

Fig.  574. 


Slop  I* 


9.3* 


Sectional 
ElevationK-K. 


Roof.          |J! 

>!'  Gutter. 


Fixed 
Transom. 


Part  Elevation  of  Side  Framing. 


|0.</5*Cr 


Sectional  2- 

Plan  L-L. 


Detail  of 


Lower 
of  Win 


-z 


Elevation. 


Horizontal  Section ; 
Framing  for  Sliding  DoppS. 


Fig.    575. 


CHAPTER  XXXIII. 

MONITOR  WINDOWS. 

Monitors  are  used  for  the  double  purpose  of  lighting  and  ven- 
tilating. Wide  monitors  are  most  effective  for  lighting  and  nar- 
row ones  for  ventilating;  and  when  the  width  suitable  for  lighting 
the  floor  is  so  great  that  foul  air,  gas  or  steam  collects  under  the 
roof,  it  may  then  be  necessary  to  add  a  second  narrow  ventilation 
monitor  on  the  ridge.  When  light  from  the  roof  is  not  required, 
a  narrow  ventilation  monitor  may  be  enough. 

Shutters  on  monitors  are  quite  as  effective  for  ventilating  as 
windows,  but  the  windows  serve  the  double  purpose  of  ventilating 
and  lighting,  and  are  therefore  preferable. 

The  monitor  sheathing  should  correspond  with  the  walls  and 
roof  of  the  main  buildings,  and  if  these  have  corrugated  iron  cov- 
ering, the  monitor  should  have  the  same,  preferably  the  small  cor- 
rugations; but  if  the  roof  is  covered  with  plank  or  gravel,  wood 
monitor  sheathing  would  then  be  more  appropriate. 

The  sash,  frames  and  casing  may  be  either  wood  or  sheet  metal, 
and  the  purlins  or  supports  for  window  frames  should  be  so 
arranged  that  frames  can  be  made  at  the  mill  and  shipped  to  the 
building  ready  for  placing.  Window  frames,  like  other  manufac- 
tured products,  cost  less  when  made  in  factories  than  by  hand 
labor  at  the  site,  and  the  practice  of  building  them  during  erec- 
tion is  wasteful  and  unsatisfactory.  The  choice  between  wood  or 
metal  for  the  frames  and  casing  depends  upon  the  fireproof  require- 
ments. Forge  shops  or  similar  buildings  where  sparks  occur 
should  have  little  or  no  wood  in  the  roof,  and  metal  frames  and 
casing  are  then  preferable. 

Wood  window  casing  may  be  covered  with  sheet  metal  and 
made  more  nearly  fireproof  (Figs.  480,  481  and  482)  and  such 
covering  should  be  black  or  galvanized  to  correspond  with  the 
sheathing,  galvanized  metal  being  preferred. 

Monitor  sash  may  be  either  fixed  or  movable,  depending  on 
the  requirements  of  ventilation.  If  the  monitor  is  for  lighting 
only,  with  individual  metal  ventilators  on  the  ridge,  the  sash  may 
then  be  stationary,  or  if  only  a  small  amount  of  ventilation  is 
needed,  it  is  economical  to  make  only  part  of  the  sash  movable, 

346 


MONITOR  WINDOWS 


347 


.  576. 


Fig.  577. 


348 


MILL  BUILDINGS 


Fig.  578. 


Fig.  579. 


MONITOR  WINDOWS 


349 


•  Corner  Capping 
Fig.  580. 


~-3' "Flashing 


A 

f/xea 

Sash 

•to 

Slide 

Sash 

fixed  Y 

^Grooves  in  Parting-strip. 
Parting-strip  nai/eafoSi//, 
not  letJn. 


Fig.  581. 


350 


MILL  BUILDINGS 


Fig.   582. 


j ---"U'O  C.toC.  of  Posts  ;••  • ;, 

I  A  2i±tt~,.     v-/?x4 


Intermediate^ Panel  Fbint 
Method  of 


MONITOR  WINDOWS 


351 


and  the  remaining  ones  stationary.  Movable  sash  are  either  sliding, 
hinged  or  trunnioned.  When  a  large  amount  of  ventilation  is 
needed,  sliding  sash  should  not  be  used,  for  they  leave  only  a 
part  of  the  monitor  side  open.  Sash  which  are  hinged  at  the 
top  or  bottom  are  more  nearly  water-tight  than  when  they  are 
trunnioned,  but  as  trunnioned  sash  are  balanced  at  their  centers 
they  are  easier  to  operate.  Trunnioned  sash,  when  open,  may 
also  interfere  with  the  inside  clearance,  unless  the  monitor  fram- 


,^-^-]V^J.*^Xi~~~~^^^^^ 


Fig.  584. 

ing  is  arranged  as  in  Fig.  8.  Figs.  576  to  585  show  monitor 
window  framing  in  wood  and  metal  for  both  fixed  and  moving 
sash. 

Figs.  576  and  577*  show  stationary  windows  with  and  with- 
out casing  and  wood  frames  and  sheathing,  while  Fig.  578*  is 
similar  but  has  pivoted  sash.  Figs.  579  and  580*  have  fixed  sash, 
with  and  without  frames  and  casings,  and  metal  sheathing.  Figs. 


*  Mill  Building  Construction.     H.  G.  Tyrrell.     1900. 


352 


MILL  BUILDINGS 


581  to  584  show  metal-covered  monitors  with  movable  sash, 
Fig.  581  has  wood  sash,  frames  and  casing,  with  alternate  sash 
sliding  horizontally  past  the  fixed  ones,  while  Fig.  582*  is  made 
without  frames  or  casings,  and  has  trunnioned  sash.  Fig.  583 


Fig.  585. 


has  wood  frames  and  casing,  with  trunnioned  sash.  Fig.  584 
shows  the  American  Bridge  Company's  standard  monitor  fram- 
ing for  sash,  either  fixed  or  movable.  Fig.  585  shows  the  cross 
monitors  used  on  the  new  Keystone  plant  of  the  Jones  and  Laugh- 
lin  Steel  Company.  The  trusses  are  spaced  19  feet  7  inches  apart 
and  monitors  with  ribbed  glass  windows  in  the  sides  cover  every 
third  panel. 

WINDOW  OPENING  MECHANISM. 

Windows  are  opened  by  sliding  them  horizontally  or  vertically 
past  each  other,  by  hinging  them  at  the  edges,  or  by  turning  them 
horizontally  on  center  trunnions.  Those  which  slide  past  each 
other  have  only  one-half  the  area  available  for  ventilation,  and  are 
therefore  not  best  suited  for  monitor  use.  Hinged  windows 
swinging  outward  are  most  likely  to  be  water-tight,  but  are  harder 
to  operate  than  balanced  ones.  Side  wall  windows  hinged  at  the 
edges  and  swinging  inward  are  not  water-tight,  and  if  swinging 
outward,  are  liable  to  be  broken  by  the  wind.  The  usual  method 
of  operating  side  wall  windows  is  therefore  to  either  slide  them 
past  each  other  or  to  balance  them  on  trunnions,  the  latter  method 


MONITOR  WINDOWS 


353 


Fig.  586. 


Fig.  587. 


354 


MILL  BUILDINGS 


Fig.  588. 


Fig.  589. 


MONITOR  WINDOWS 


355 


being  preferred  when  large  ventilation  is  desired.  Windows  which 
are  suspended  and  slide  vertically  past  each  other  should  be  ar- 
ranged in  pairs,  one  sash  balancing  the  other,  for  the  expense  of 
window  weights  will  then  be  saved. 


Fig.  590. 


Pig.  591. 


A  very  simple  mechanism  for  operating  monitor  windows, 
which  is  similar  to  that  in  Fig.  525,  is  illustrated  in  Fig.  586. 
It  should  be  used  when  the  operating  cord  from  the  lever  leads 
down  under  the  roof  to  the  side  walls  and  thence  to  the  floor.  Its 
cost  is  small,  for  the  levers  can  be  made  in  a  structural  shop,  but 
it  has  the  disadvantage  of  permitting  one  cord  and  lever  to  open 
only  the  windows  in  one  panel,  though  it  is  more  effective  when 


356 


MILL  BUILDINGS 


one  cord  and  lever  are  used  for  two  sash,  one  on  each  side  of  the 
monitor.    When  two  or  three  sash  on  each  side  of  the  monitor  are 

operated  in  sets  by  one  lever,  the  several 
sash  on  each  side  must  then  be  rigidly  con- 
nected by  a  continuous  angle  bar  bolted  to 
the  upper  rails,  and  the  lever  must  be 
placed  near  the  center  of  the  set,  with 
springs  fastened  at  the  middle  of  the  end 
sash  to  close  the  windows  automatically. 
Two  pulleys  are  needed,  one  below  the 
ventilator  window  and  another  at  the  side 
wall  below  the  roof. 

Other  methods  of  opening  monitor 
sash  are  shown  in  Figs.  587  to  590.  Fig. 
587  is  the  Lovell  window  operator,  in 
which  two  lines  of  pipe  supported  on 
rollers  are  moved  back  and  forward  by  a 
pinion  between  two  racks,  turned  by  a 
chain  wheel.  Fig.  599  is  the  usual  worm 
and  gear  mechanism  turning  a  continuous 
shaft,  to  which  are  fastened  extension 
arms  connected  to  the  lower  sash  rails. 
Fig.  588  is  the  Lord  and  Burnham  method 

of  opening  monitor  windows,  by  means  of  shafts  brought  down  on 
the  side  walls  with  universal  couplings  in  order  to  avoid  obstruct- 


Fig.   592. 


Fig.   593. 


ing  the  traveling  crane.  When  the  rods  connect  to  windows  on  the 
opposite  side  of  the  monitor,  the  operator  can  then  observe  the  posi- 
tion of  the  windows  that  he  is  moving.  Figs.  591  and  592  show  other 


MONITOR  WINDOWS 


357 


applications  of  the  same  mechanism  for  opening  clear  story  win- 
dows with  shafts  and  hand  wheels  brought  directly  down  beneath 
the  windows  and  fastened  to  columns  or  pilasters  near  the  floor. 

Figs.    593   and   594   illustrate   similar   apparatus   for   opening 
side  wall  windows  both  in  single  and  in  triple  lines. 


Fig.   594. 


CHAPTER  XXXIV. 

BOOKS. 

The  number  and  location  of  doors  in  a  manufacturing  build- 
ing must  be  determined  by  the  needs  of  travel,  with  a  greater 
number  for  buildings  in  which  many  people  are  housed,  and  a 
smaller  number  where  there  are  few  employees.  The  doors  for 
general  entrance  and  exit  should  be  separated,  so  crowding  will 
not  result  from  travel  in  two  directions.  It  is  a  mistake  to 
have  too  many  doors  and  passageways  through  a  shop,  for  each 
passage  occupies  valuable  floor  space.  Doors  for  manufacturing 
buildings  are  made  either  of  plain  wood,  wood  covered  with  metal, 
corrugated  iron,  corrugated  asbestos  board,  or  light  reinforced 
concrete.  The  best  plain  wood  doors  are  made  of  white  pine. 
Thin  slabs  of  reinforced  concrete  are  used  in  some  forms  of  patent 
folding  doors,  examples  of  which  are  those  for  the  Terminal 
Warehouse  Company  of  Kansas  City  (Fig.  613),  the  weight  of 
which  for  8  X  8-foot  openings  is  1,600  pounds.  Many  forms  of 
doors,  particularly  plain  wooden  ones,  may  have  large  glass  panels 
in  the  upper  halves,  which  not  only  serve  to  admit  light,  but  per- 
mit a  person  on  one  side  of  the  door  to  observe  approaching  objects 
on  the  other  side. 

The  size  of  doors  depends  upon  the  size  of  material  brought 
into  the  building  and  the  products  shipped  out,  and  upon  the 
need  of  admitting  trucks  or  cars.  Entrance  doors  for  the  largest 
box  cars  should  be  not  less  than  16  feet  in  height  and  12  feet  in 
width.  Structural  works  and  bridge  shops  need  doors  for  ship- 
ping manufactured  products  large  enough  to  permit  flat  cars 
loaded  to  their  maximum  height  and  width  to  pass  through  them. 
As  large  doors  are  usually  located  on  the  principal  avenues  of 
travel  through  the  shop  and  need  to  be  open  only  part  of  the  time, 
it  is  often  convenient  to  insert  a  small  door  in  the  large  one  for 
the  use  of  pedestrians,  as  shown  in  Fig.  619,  framing  details  of 
the  smaller  door  being  shown  in  Fig.  620.  This  arrangement  is 
not  entirely  satisfactory,  for  the  lower  framing  angle  of  the  large 
door  must  not  be  cut  for  the  smaller  one,  and  pedestrians,  in 
using  the  small  door,  must  step  over  the  framing  of  the  larger 
one,  which  is  always  inconvenient  and  sometimes  the  cause  of 
accident. 

358 


DOOES 


359 


Doors  may  be  classified  generally  into  three  kinds:  (1)  one- 
piece  doors,  either  hinged,  rolling  on  horizontal  tracks,  or  counter- 
weighted  to  rise  vertically;  (2)  doors  which  are  made  in  two  or 
more  pieces  and  open  by  folding  together;  (3)  coiling  or  rolling 
doors  made  of  wood  or  sheet  metal  slats. 

Exit  doors,  in  factory  buildings  with  a  large  number  of  em- 
ployees, should  open  outward  for  safety  in  case  of  fire,  as  specified 
by  the  city  building  laws.  Entrance  doors,  or  those  for  only  occa- 
sional use,  are  more  convenient  and  less  liable  to  injury  when 


Fig.  595. 


Fig.  596. 


opening  inward.  Horizontal  sliding  or  rolling  doors  on  brick 
walls  are  more  conveniently  placed  on  the  inside  of  the  building, 
while  similar  doors  on  corrugated  iron  walls  are  better  on  the 
outside,  for  the  corrugated  iron  doors  then  lie  nearer  to  the  plane 
of  the  wall  sheathing,  and  in  opening  there  is  less  liability  of 
interfering  with  steel  columns  or  other  framing.  The  space  over 
the  door  should  be  water-proofed  with  a  metal  hood,  inserted  under 
the  wall  sheathing  and  bent  out  to  cover  the  door  track  (Fig. 
604).  Figs.  605  and  606  show  alternate  methods  for  suspending 
rolling  doors  on  the  inside  of  a  building,  in  one  case  the  door 
frame  being  made  with  wooden  jambs  and  casing,  and  in  the  other, 
the  jambs  and  head  casing  consisting  of  steel  channels  with  webs 


360 


MILL  BUILDINGS 


turned  toward  the  opening,  as  designed  and  used  by  the  author 
on  a  forge  shop  in  1896. 

Doors  with  height  not  exceeding  8  feet  can  be  hinged  at  the 
sides  for  single  doors  up  to  4  feet  in  width,  and  double  doors  up 
to  7  or  8  feet  wide.  Larger  sizes  up  to  20  feet  square  must  either 
be  suspended  to  move  vertically,  roll  horizontally,  or  coil  above 
the  doorway. 

Wherever  serious  liability  to  fire  exists,  doors  should  be 
equipped  with  automatic  closing  apparatus,  consisting  of  a  fusi- 
ble soft  metal  link  in  the  counterweight  chain  which  holds  the 
door  open.  These  links  melt  at  a  temperature  of  160  degrees 
and  the  doors  close  by  gravity.  The  pattern  shop  and  storage 
building  at  the  West  Allis  plant  of  the  Allis-Chalmers  Company 
is  a  good  example  of  fireproof  construction,  in  which  automatic 
closing  doors  are  used. 

WOOD  PANEL  DOOES. 

Ordinary  panel  doors  (Fig.  595)  are  made  in  single  leaves  up 
to  3J  feet  in  width,  and  in  double  leaves  to  about  5  feet,  and 
are  made  in  three  grades,  known  as  A,  B  and  C,  the  first  being 


Vis.   597, 


Fig.   598. 


the  best  quality.  Single  doors  suitable  for  factory  use  cost  from 
$2  to  $10  each,  depending  on  the  thickness,  kind  of  wood,  and 
finish.  They  are  usually  made  in  two  thicknesses,  If  and  1| 
inches,  respectively,  with  a  height  of  2^  times  their  width.  The 
width  of  side  and  top  stiles  is  usually  %  the  width  of  opening. 


DOOES  361 

BATTEN  DOORS. 

Figs.  596,  597  and  598*  show  three  views  of  wood  batten  doors, 
the  smaller  being  suitable  for  3  feet  in  width,  while  the  second 
can  be  used  for  widths  of  6  feet,  and  the  last  up  to  14  feet.  These 
doors  are  made  with  stile  and  rail  halved  or  mortised  together 
at  the  joints.  The  inner  edges  should  have  J-inch  chambers  as 
shown.  Fig.  596  is  drawn  for  a  door  8  feet  in  width ;  wider  doors 
should  have  two  or  more  intermediate  stiles,  spaced  3  to  4  feet 
apart.  The  sheathing  should  either  be  screwed  to  the  frame  or 
fastened  with  large  head  wire  nails,  bent  over  and  thoroughly 
clinched  into  the  battens.  Tables  LX  and  LXI  give  the  proper 
size  of  material  and  hardware  for  doors  of  different  dimensions, 
from  5X8  feet  to  14  X  20  feet. 

TABLE   LX. 
PROPER  SIZES  OF  MATERIAL  FOR  DOORS  UP  TO  14X20  FT. 


Size  of  dot 
in  ft. 

5X   8  or 
6X   8  to 
7X   8  to 
10X10  to 
14X14  to 

irs 
less  .  .  .  . 

Stiles 
ins. 

4X1% 

Top 
ins. 

Center 
ins. 

Bottom 
ins. 

Diagonals 
ins. 

4X1% 
4X1% 
4X1% 
5X2 
5X2% 

Sheath 
ins. 

4X% 
4X% 
4X% 

4X% 

4X1% 
7X1% 
7X1% 
9X2 
9X2% 

4X1% 
6X1% 
6X1% 
8X2 
8X2% 

6X1% 
8X1% 
8X1% 
10X2 
10X2% 

7X   8.. 
10X10.. 
14X14.. 
14X20.. 

.7X1% 
.7X1% 
.8X2 
.9X2% 

TABLE  LXI. 

DIMENSIONS  OF  HINGES  AND  APPURTENANCES  FOR  DOORS  OF 
DIFFERENT  SIZES.     STANLEY  WORKS  HEAVY  HINGES. 


Size  of  doors 
in.  ft. 
3  X   6  or  less  
3X  6  to  3X   8. 

Plain.             Galv. 
Strap      T.      Strap      T 
ins.      ins.       ins.      ins. 
...10         10         10         10 
16         16         16         16 

Screws. 
Door         Jamb      Bolts 
ins.             ins.        ins. 
1%               2               % 
1%                2                % 
%-in.  lag  screws       % 
%-in.  lag  screws       % 
%-in.  lag  screws       % 

3X   8  to  4X10 

24-in.  strap  hinge 

4X10  to  5X12  
Over  5X12  

.  .  .30-in.  strap  hinge 
.  .  .36-in.  strap  hinge 

TABLE  LXII. 

TOTAL  WEIGHT  OF  METAL  COVERED  DOORS  PER  SQ.  FT.  IN  LBS. 

Size  of  iron.          Weight  3  in.  thick  sheathing.  Weight  2  in.  thick  sheathing. 

Black  Iron.             Galv.  Iron.  Black  Iron.       Galv.  Iron. 

No.  16 10.69                         11.37  8.87  9.55 

No.   18 9.41                          10.09  7.59  8.27 

No.  20 8.27                            8.95  6.45  7.13 

No.   22 7.71                           8.39  5.89  6.57 

No.   24 7.23                            7.91  5.41  6.09 

No.   26 6.91                            7.59  5.09  5.77 

No.  28 6.59                           7.27  4.77  5.45 

No.  I  C  Tin 6.47                             ...  4.65 

No.  IX  Tin....      6.72                             ...  4.90 

*  H.  G.  Tyrrell,  Engineering  News,  April  11,  1901. 


362 


MILL  BUILDINGS 


Glass  panels  (Fig.  599)  can  often  be  used  to  advantage  in 
large  wooden  doors,,  and  diagonals  in  the  upper  half  must  then 
be  omitted  and  sheathing  placed  at  an  angle  of  45  degrees  to  the 
vertical.,  as  in  smaller  doors.  They  may  be  covered  inside  and  out 
with  flat  galvanized  iron,  if  fire  risk  is  excessive. 

Doors  which  are  made  to  slide  either  horizontally  or  vertically 
should  lap  2  inches  over  the  building  frame  at  the  top  and  side,  and 
must  therefore  be  4  inches  wider  than  the  opening  and  2  inches 
higher.     Without  hardware  and  opening  apparatus  or  expense  of 
placing,  they  cost  from  25  to  30  cents  per  square  foot. 


TIN  CLAD  DOORS. 

These  are  made  of  two  or  three  thicknesses  of  f -inch  tongued 
and  grooved  wood  sheathing  (Fig.  600),  and  are  covered  on  the 
sides  and  edges  with  sheet  steel  or  tin.  The  weight  per  square 
foot  for  two  and  three  ply  doors  with  metal  covering  of  different 


DOOES 


363 


thicknesses  is  given  in  Table  LXII.  The  sheathing  must  be  well 
fastened  together  with  wire  nails  driven  tight  and  clinched.  A 
door  of  this  kind  with  inclined  track,  held  open  by  weight  and 
cord  in  which  is  inserted  a  fusible  link,  is  shown  in  Fig.  601.  In 
case  of  fire,  the  link  melts  and  the  door  shuts  automatically  by 
rolling  on  the  inclined  track  and  is  held  closed  by  the  iron  socket 


Fig.  GOO. 


Fig.   601. 


near  the  floor.  Two-ply  fire  doors  cost  18  cents  per  square  foot  for 
woodwork  only,  and  38  cents  per  square  foot  with  tin  covering, 
while  three-ply  doors  cost  27  cents  per  square  foot  for  the  wood- 


Fig.  602. 


Fig.  603. 


364 


MILL  BUILDINGS 


work  and  47  cents  complete  with  tin  casing.  Hardware  costs 
about  $3  per  door  and  painting  about  $1  extra,  and  the  labor  of 
erection  costs  another  $3. 

COEKUGATED  IRON  DOOES. 

Fig.  602  illustrates  a  pair  of  iron  doors  made  of  flat  plate  or 
corrugated  iron;    each  door  is  suspended  by  three  hinges  to  an 


5'tod'L,  "a" in  Table 


JL  i  "top  of  Door 


Iron    Door 
Inside. 


Wood  Door. 


Detail  Wall  Bracket. 
Fig.  605. 


Holes  In  Track  Hanger. 
Fig.  604. 


iron  channel  frame  built  into  and  bolted  to  the  brickwork,  as  in 
Fig.  603.  Corrugated  iron  doors  are  stronger  for  the  same  weight 
than  those  made  of  flat  iron,  though  the  construction  details  with 


6T-//7. 


Fig.  606. 


Fig.  607. 


DOORS 


365 


flat  iron  are  simpler  and  more  easily  made  than  with  corrugated 
iron.  The  frame  for  a  corrugated  iron  door  is  shown  in  Fig.  575 
Fig.  604  gives  details  for  hanging  a  corrugated  iron  door  on  the 
outside  of  an  iron  building,  while  Fig.  605  shows  corresponding 
details  for  hanging  it  inside,  which  details  were  designed  and  used 
by  the  writer  in  the  building  of  a  structural  plant.  Small  corru- 
gated iron  doors  present  a  better  appearance  when  made  1^-inch 
corrugations,  but  larger  ones,  requiring  greater  strength,  should 
be  2J-inches  wide.  The  cost  of  doors  without  hardware  or  erection 
is  from  20  to  30  cents  per  square  foot,  depending  on  the  size  of 
the  door  and  the  presence  or  absence  of  a  small  door  inside  the 
large  one  (Fig.  619). 

SWING  SLIDING  DOOES. 

Swing  doors  used  on  freight  sheds  at  Madison,  Wisconsin, 
are  shown  in  Fig.  607.  They  can  be  made  of  wood,  corrugated  iron 
or  wood  covered  with  tin,  and  are  opened  by  being  revolved  into 
a  horizontal  position  above  the  doorway,  where  they  offer  no  ob- 
struction to  the  moving  of  goods,  but  leave  the  entire  side  of  the 
building  open.  They  are  suspended  by  chains  from  the  bottom 
of  the  door,  and  are  revolved  into  a  horizontal  position  when  lifted 
by  the  action  of  rods,  the  ends  of  which  are  fastened  to  the  wall 


Fig.   608. 


and  to  the  doors,  and  are  operated  by  chain  and  sprocket  wheels. 
They  can  be  equipped  with  fusible  links,  to  allow  them  to  close  in 
case  of  fire. 


HOEIZONTAL  FOLDING  DOOES. 

A  form  of  door  which  is  now  quite  popular  is  the  horizontal 
folding  door  illustrated  in  Fig.  608.     It  is  made  of  wood,  steel, 


366 


MILL  BUILDINGS 


asbestos  board,  or  reinforced  concrete,  is  hinged  to  the  wall  at 
the  upper  edge,  and  made  with  upper  and  lower  sections  which 
are  hinged  together  and  the  whole  counterweighted.  When  raised 


J 


Fig.   609. 


by  a  hand  chain  and  wheel,  the  two  sections  fold  together,  the 
bottom  part  of  the  lower  section  rising  vertically  and  the  hinges 
or  outer  portions  of  the  door  describing  a  curve. 

These  doors  are  well  suited  for  buildings  such  as  freight  sheds, 
warehouses,  wharf  buildings,  etc.,  where  all  doors  may  be  needed 


Fig.  610. 


DOORS 


367 


Fig.  611. 


Fig.   612. 


Fig.   613. 


368  MILL  BUILDINGS 

open  at  the  same  time,  and  the  whole  side  available  for  handling 
and  loading  goods.  The  doors,  when  open,  are  folded  up  and  out 
of  the  way,  and  are  not  occupying  valuable  storage  space.  When 
made  of  wood,  they  may  be  paneled,  or  can  be  covered  with  gal- 
vanized iron,  with  glass  panels  in  the  upper  leaf.  Doors,  includ- 
ing operating  mechanism,  cost  about  75  cents  per  square  foot,  and 
erection  about  15  cents  per  square  foot  additional. 

THE  EITTEE  FOLDING  DOOE. 

This  patent  door  is  made  in  three  or  more  sections  (Tigs. 
612,  613  and  614),  and  is  opened  by  being  folded  inside  the  build- 
ing with  successive  leaves  piled  upon  each  other.  It  is  balanced 
by  counterweights  hanging  in  boxes,  to  prevent  goods  from  ob- 
structing or  interfering  with  the  movement  of  the  weights  or  the 
operation  of  the  door.  As  the  doors  occupy  a  large  proportion  of 
the  wall  surface,  the  upper  two  or  three  leaves  may  be  filled  with 
glass  panels.  They  are  well  suited  for  use  on  engine  houses  where 
additional  light  is  needed  on  the  low  or  inner  side.  They  are 
operated  by  chain  and  sprocket  wheel  and  the  width  between  ad- 
joining doors  for  wheel  and  counterweight  does  not  exceed  18 
inches.  They  can  be  equipped  with  automatic  closing  apparatus, 
which  assures  positive  action  in  case  of  fire.  At  no  period  of  their 
operation  do  they  occupy  valuable  space,  and  when  partly  open 
the  leaves  act  as  louvres  and  admit  air  while  thev  exclude  rain. 


Fig.  614. 
SPECIAL  PIEE  SHED  DOOE. 


A  special  folding  door  used  on  several  Hudson  River  pier 
sheds  is  illustrated  in  Fig.  615.  It  was  designed  to  suit  the  require- 
ments of  ocean  steamships,  receiving  and  delivering  goods  at  the 


DOOES 


369 


Chelsea  piers,  and  is  made  in  two  sections,  so  it  can  be  entirely 
open  or  either  section  open  with  the  other  closed.  The  upper  sec- 
tion is  hinged  at  the  top,  and  the  lower  one  moves  up  and  down 

i 


in  grooves  on  the  building  columns  and  is  balanced  by  chain  and 
counterweight.  The  doors  were  originally  operated  by  a  chain 
and  hand  hoist,  but  as  they  are  very  large  and  heavy,  opening 
by  hand  power  was  too  slow,  and  plans  were  made  for  installing 


370 


MILL  BUILDINGS 


electric  hoisting  apparatus  with  line  shafting  to  move  several 
doors  at  one  time.  When  all  the  doors  are  open,  the  entire  side 
of  the  building  is  free  for  handling  goods,  a  width  of  only  24 
inches  being  required  at  the  columns  for  guides,  hoisting  appa- 
ratus and  counterweights.  The  jambs  consist  of  two  8-inch 
channels  on  each  side  of  a  column,  bolted  together  through  their 
flanges  and  serving  not  only  as  jambs  but  also  as  counterweight 


•IQ'Q'- 

Fij.    616. 


L 09* J 

Fig.    617. 

boxes.  When  the  upper  section  of  the  door  is  open,  and  the  lower 
section  closed,  ventilation  is  secured,  while  the  contents  of  the 
building  are  protected  from  river  thieves.  The  doors  are  covered 
on  the  outside  with  Xo.  22  gage  galvanized  crimped  iron  and  on 
the  inside  with  tin. 

ROLLING  DOORS. 

Several  views  of  rolling  doors  are  illustrated  in  Figs.  618  to 
622.    They  are  made  of  metal  or  wooden  slats,  which  are  fastened 


DOOES 


371 


Fig.   618. 


Fig.   619. 


Fig.  620. 


372 


MILL  BUILDINGS 


Fig.  021. 


Fig.   622. 


DOOES 


373 


together,  sliding  between  the  side  guides,  and  when  open  are  rolled 
in  coils  overhead.  They  can  be  placed  either  inside  or  outside 
of  the  building,  or  in  the  doorway  between  the  jambs,  and  small 
doors  up  to  5  or  6  feet  in  width  can  be  opened  by  hand, 
while  larger  ones  are  equipped  with  chain  hoists.  They  are  coun- 
terbalanced by  springs  to  facilitate  their  operation,  and  can  have 
fusible  links  to  close  automatically  should  fire  occur.  Fig.  619 
is  a  large  steel  rolling  door  for  occasional  use,  with  a  smaller  one 
fitted  into  it  for  pedestrians,  which  must  be  unbolted  and  removed 
when  the  large  door  is  open.  The  market  building  with  continu- 
ous arched  side  openings,  illustrated  in  Fig.  32,  was  planned  for 
continuous  lines  of  rolling  shutters.  The  end  of  a  shop  (Fig. 
621)  enclosed  with  folding  steel  shutters  can  be  thrown  open  to 
permit  the  traveling  crane  to  pass  out  of  the  building  to  the  ship- 
ping yard.  The  two  intermediate  posts  or  shutter  guides  are 
hinged  at  their  upper  ends  and,  when  the  doors  are  opened,  are 
revolved  up  into  a  horizontal  position,  leaving  a  clear  space  for 
the  traveling  crane.  A  similar  arrangement  for  use  on  car  sheds 
is  illustrated  in  Fig.  622;  the  shutters  are  operated  either  singly 
or  together  by  an  electric  motor,  and,  when  raised,  the  guides  are 
drawn  up  under  the  roof,  leaving  an  unobstructed  trolley  wire 
connection. 


Fig.   623. 


CHAPTER  XXXV. 

FACTORY  FOOT  BRIDGES. 

Foot  bridges  connecting  factories  or  other  buildings  are  fre- 
quently a  great  saving  of  time  and  labor.  It  often  occurs  that  the 
different  buildings  of  a  manufacturing  establishment  are  located 
on  both  sides  of  a  street.  Goods  must  pass,  in  the  course  of  manu- 
facture, through  several  buildings  before  being  completed,  are 
brought  into  one  building  on  the  ground  floor,  and  after  passing 
up  through  the  various  floors  of  one  building,  cross  over  to  an 
adjoining  building  and  down  through  the  various  stories  to  the 
ground  again.  In  this  way  the  goods  are  elevated  and  lowered 
only  once  in  each  building,  or  twice  in  all.  Without  the  connect- 
ing foot  bridges  for  the  upper  stories  of  the  adjoining  buildings, 


'ig.   624. 


it  would  be  necessary  to  elevate  and  lower  the  goods  in  each  of 
the  two  buildings,,  making  four  transfers. 

Elevated  foot  bridges  are  a  great  saving  of  time  and  energy. 
They  make  it  possible  to  move  goods  back  and  forth  from  place 
to  place  with  ease  and  without  undue  loss  of  time.  Formerly, 

374 


FACTORY  FOOT  BEIDGES 


375 


when  these  bridges  were  made  of  wood,  the  framing  was  heavy 
and  expensive  for  spans  long  enough  to  cross  ordinary  streets, 
but  now  that  they  can  be  framed  of  steel  with  small  bars  and 
shapes  that  are  not  cumbersome,  and  at  the  same  time  safe,  they 
are  worthy  of  more  general  use.  Buildings  joined  in  this  way 
with  numerous  bridges  are  almost  as  convenient  as  if  the  several 
buildings  were  all  in  one,  and  at  the  same  time  they  possess  the 
advantage  of  being  lighted  from  side  windows,  which  cannot  be 
done  where  the  entire  floor  space  is  under  one  roof.  Well  lighted 
buildings  not  only  save  the  cost  of  artificial  lighting  but  also 
facilitate  production.  Numerous  small  separate  buildings,  con- 
nected with  passages  on  the  lower  floors,  and  with  covered  foot 
bridges  in  the  upper  stories,  afford  both  better  sunlight  and 
ventilation. 

The  covered  foot  bridges  shown  in  the  accompanying  illus- 
trations (Figs.  624:  to  62 G)  are  framed  of  steel  and  covered 
with  corrugated  iron.  Where  the  location  will  permit,  they  may 
be  lined  on  the  inside  with  wood  sheathing,  and  finished  in  the 
same  general  style  as  the  buildings  they  connect.  Those  shown 


Weight    of    Coven 
Foot    Bridge 
Steel    Frame    on/y 

•at 

16,000 
14,000 
12,000 
10,000 
8000 
6,000 
4,000 
2,000 

Cost  of  Covered  Foot  Bridge^ 
with  Steel  f 
Steel  at  6  Cents  per  Ib. 
Com  Iron  at  10  Cents  per  Ib. 
Wood  Flooring  ff40  per  M. 

f 

ra 

m 

es    . 

Dollars 
1600 

1400 
KOO 
1000 
800 
600 
400 
200 

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^ 

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ft 

fa 

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T 

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V 

v^ 

v 

Ps 

7 

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J 

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• 

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X 

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t 

X 

_J-" 

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•** 

1 

20'    30'   40'    50'   60'    70'    80'    90'   lOOSpcm 

10' 

TO'    30'   40'    50'   60'    70'  80'    90'  100'Span 

Fig.  625.  Fig.   626. 

are  intended  more  especially  for  ordinary  factory  use,  and  are 
covered  on  the  outside  with  corrugated  iron  without  any  inside 
lining.  They  are  framed  entirely  of  steel,  with  wood  for  the 
flooring  only. 

The  curves  give  the  weight  of  steel  (Fig.  625*)  and  the  total 
cost  (Fig.  626*)  for  spans  varying  from  15  to  100  feet,  for  a 
uniform  width  of  6  feet.  In  figuring  the  cost  of  these  bridges, 
steel  in  place  has  been  taken  at  6  cents  per  pound,  corrugated  iron 
at  10  cents  per  square  foot  and  wood  flooring  at  $40  per  thousand. 

*  H.  G.  Tyrrell,  in  Carpentry  and  Building.     1905. 


376  MH<L  BUILDINGS 

These  costs  are  only  approximate,  depending  upon  the  local  price 
of  the  several  items  included. 

They  are  proportioned  for  a  floor  load  of  60  to  80  pounds  per 
square  foot  of  floor  area.  Where  it  is  necessary  to  transfer  heavy 
weights  from  one  building  to  another,  these  capacities  may  be 
increased  proportionately.  It  is  sometimes  convenient  to  provide 
for  the  carriage  of  small  trucks  on  a  pair  of  rails,  or  a  trolley  to 
carry  loads  overhead. 

It  is  well  to  have  the  bridges  lighted,  and  this  can  best  be 
done  by  alternating  the  windows  on  the  two  sides. 

The  illustrations  show  bridges  from  20  to  80  feet  in  length, 
which  will  cover  all  ordinary  cases. 


CHAPTER  XXXVI. 
PAINT. 

Paint  consists  of  a  liquid  or  vehicle,  either  fixed  or  volatile, 
thickened  with  a  pigment  or  base,  the  materials  being  such  that 
when  spread  in  a  thin  layer  and  allowed  to  dry,  an  impervious 
film  results,  which  excludes  air  and  moisture.  Other  substances, 
called  driers,  are  added  to  assist  the  paint  in  hardening,  and 
stainers  are  used  for  coloring.  There  must  be  enough  liquid  or 
vehicle  to  hold  the  pigment  in  suspension  and  allow  every  particle 
of  it  to  be  surrounded,  the  theory  being  that  the  vehicle  only  is 
in  contact  with  the  painted  surface. 

Paint  should  spread  smoothly  and  evenly,  and  the  first  coat 
should  cover  the  surface.  It  should  be  adhesive,  economical,  tough, 
elastic,  and  should  dry  in  a  reasonable  time.  It  should  nat 
effected  by  heat  or  cold,  rain,  snow  or  wind,  and^must^jefei^the 
action  of  smoke  and  fumes.  It  must  contain  no  solvents  and 
nothing  that  will  corrode  the  iron,  must  be  non-poisonous,  dura- 
ble and  waterproof.  It  must  not  blister,  crack  or  scale,  and  must 
retain  its  color  and  composition.  It  should  have  power  to  extract 
dampness  or  moisture  from  the  metal,  and  not  be  easily  ignited. 
First  coats  should  dry  harder  and  more  quickly  than  later  ones, 
but  the  difference  in  time  of  drying  should  not  be  great.  Priming 
coats  should  preserve  the  metal  and  prevent  oxidation,  while  later 
ones  should  protect  the  lower  ones  from  the  elements.  Paint  must 
work  easily  under  the  brush  to  form  a  film  of  even  thickness,  and 
must  dry  simultaneously  and  not  more  quickly  on  the  surface 
than  underneath.  Paint  is  more  durable  in  air  than  in  water, 
but  its  merits  depend  chiefly  upon  the  care  with  which  it  is 
applied. 

VEHICLES. 

The  most  important  ingredient  of  paint  is  the  liquid  binder 
or  vehicle.  Water,  linseed  oil,  turpentine,  liquid  japan  driers, 
benzine  with  asphaltum  and  tar,  have  all  been  used,  but  about 
90  per  cent  of  metal  paints  are  made  with  linseed  oil.  It  is  gen- 
erally accepted  as  the  best  vehicle,  except  under  ground  or  in  per- 
manently damp  locations.  Nut  and  poppy  oil  are  sometimes  used, 
but  are  not  as  satisfactory.  Other  patented  vehicles  are  used, 

377 


378  MILL  BUILDINGS 

but  their  merits  are  due  chiefly  to  the  linseed  oil  which  they  con- 
tain. Investigation  of  the  failure  of  paint  in  the  New  York  sub- 
way proves  that  steel  paints  made  of  linseed  oil  and  pigments  are 
useless  in  the  presence  of  vapor,  abnormal  humidity  and  condensa- 
tion. Turpentine  and  benzine,  when  mixed  with  oil,  reduce  its 
durability,  and  should  not  be  used  in  paint  for  iron  and  steel. 

Linseed  oil  is  made  by  compressing  flaxseed  and  collecting  the 
product.  Pure  oil  is  transparent,  has  a  sweet  taste  and  no  smell, 
and,  as  it  improves  with  age,  should  not  be  used  until  it  is  six 
months  old  or  more.  It  requires  four  to  six  days  to  dry,  and 
during  the  drying  process  passes  from  liquid  to  solid. 

BOILED    LINSEED    OIL. 

To  hasten  the  drying  of  raw  linseed  oil,  it  was  formerly  heated 
alone,  or  with  driers,  such  as  red  lead  or  litharge.  The  resulting 
oil  then  dried  in  twelve  to  twenty-four  hours,  or  five  to  ten  times 
faster  than  raw  oil.  With  the  recent  process,  more  rapid  drying 
is  secured  by  the  addition  of  manganese  driers  at  the  proper  tem- 
perature, and,  though  boiling  does  not  occur,  the  product  is  known 
as  "boiled  oil."  The  treated  oil  is  darker  in  color  than  the  orig- 
inal and  weighs  7-|  pounds  per  gallon.  Drying  results  not  from 
evaporation,  but  by  the  absorption  of  oxygen  from  the  air,  with  an 
increased  weight  of  15  to  20  per  cent,  and  the  process  of  drying 
converts  the  oil  into  a  tough  and  elastic  film.  Boiled  oil  produces 
a  glossier  finish  than  raw  oil  and  is  better  suited  for  exterior 
work  exposed  to  the  weather.  The  oil  should  be  both  commer- 
cially and  chemically  pure.  The  addition  of  turpentine  makes  the 
oil  thinner  and  permits  it  to  dry  faster,  but  the  turpentine  is  only 
a  thinner,  and  not  a  drier. 

Linseed  oil  is  often  adulterated  with  25  to  50  per  cent  of  other 
substances,  as  fish  oil,  petroleum,  cottonseed  oil,  etc.,  the  presence 
of  which  can  be  detected  by  the  smell.  Buying  in  sealed  cases 
directly  from  the  makers  removes  the  possibility  of  adulteration 
by  middlemen  and  dealers. 

Eaw  linseed  oil  costs  (1911)  90  cents  per  gallon,  and  boiled  oil 

95  cents,  and  it  is  the  most  expensive  part  of  oil  paint.  Paint 
made  of  pure  linseed  oil  cannot  be  sold  with  profit  to  the  makers 

and  dealers  for  less  than  $1.00  to  $1.10  per  gallon,  and  the  so-called 

oil  paints  selling  at  less  than  the  cost  of  the  oil,  evidently  cannot 

contain  pure  linseed  oil. 


PAINT  379 

PIGMENTS  OK  BASES. 

While  linseed  oil  is  generally  accepted  as  the  best  vehicle  for 
paint,  there  is  no  agreement  among  engineers  and  paint  makers  in 
reference  to  pigments  or  bases.  White  and  red  lead,  zinc  white, 
iron  oxide,  carbon  and  graphite  are  all  used  with  various  degrees 
of  success.  The  vehicle  alone  is  not  hard  and  thick  enough  to 
resist  abrasion,  and  must  be  strengthened  by  some  other  substance 
called  a  base.  The  chief  function  of  the  base  is,  therefore,  to 
increase  the  thickness  of  the  paint,  to  make  it  stronger,  and  to 
protect  the  oil  film  from  injury.  Oil  contracts  in  drying,  causing 
minute  surface  pores  to  form,  and  these  are  filled  or  partly  filled 
by  the  base.  Bases  should  be  neutral  or  inert,  not  subject  to 
chemical  change,  and  should  be  finely  ground.  The  paint  should 
contain  only  enough  pigment  so  every  particle  of  pigment  will  be 
surrounded  and  enveloped,  so  the  vehicle  only  will  be  in  contact 
with  the  surface.  A  layer  of  paint  with  pigment  is  three  times 
thicker  than  a  layer  of  oil. 

WHITE   LEAD. 

White  lead  has  been  used  for  many  centuries,  and  is  referred 
to  by  ancient  writers  before  the  Christian  era.  It  contains  70 
per  cent  carbonate  of  lime  and  30  per  cent  hydrate  of  lead,  and 
is  made  either  by  dissolving  sheet  lead  in  acetic  acid,  or  mixing 
lead  oxide  (litharge)  with  water  and  1  per  cent  of  acetate  of 
lead.  Pure  white  lead  is  a  heavy  powder,  white  when  made,  but 
turning  gray  when  exposed.  It  is  soluble  in  dilute  nitric  acid, 
but  not  in  water.  It  has  a  substantial  body,  is  dense  and  perma- 
nent, and  is  used  as  a  base  for  all  colors.  It  is  not  recommended 
as  a  base  for  metal  because  it  needs  too  frequent  renewals,  but  it 
is  the  best  known  pigment  for  wood  preservation.  As  white  lead 
and  zinc  are  the  pigments  for  all  light  colored  paints,  white  lead 
is  much  used  for  top  coats  on  steel  framing  when  a  light  finished 
color  is  desired.  For  exterior  surfaces  exposed  to  the  weather, 
it  should  be  combined  with  zinc  oxide.  White  lead  does  not  com- 
bine chemically  with  linseed  oil,  but  is  a  mechanical  mixture. 
Ft  is  sold  in  powder,  but  more  commonly  as  a  paste,  which  is  com- 
posed of  dry  white  lead  with  9  per  cent  by  weight  of  linseed  oil. 
Five  gallons  of  linseed  oil  added  to  100  pounds  of  paste  makes 
CJ  gallons  of  paint,  weighing  21.3  pounds  per  gallon;  15  pounds 
of  lead  paste  and  6.3  pounds  of  oil  makes  one  gallon  of  paint. 
Three  coats  of  white  lead  paint  are  as  effective  as  five  coats  of 
zinc  oxide.  White  lead  is  often  adulterated  with  sulphate  of 


380  MILL  BUILDINGS 

baryta,  lead  sulphate,  gypsum,  zinc  oxide,  and  chalk.  Sulphate 
of  baryta,  the  most  common  adulterant,  is  a  heavy,  dense,  white 
substance,  and  can  be  detected  by  its  gritty  feeling  when  rubbed 
in  the  hands. 

ZINC  OXIDE. 

This  is  the  base  for  all  zinc  paints.  It  takes  longer  to  dry 
than  white  lead,  and  costs  more,  but  makes  a  thicker  paint  film, 
and  retains  its  color  better.  It  is  more  permanent  than  lead,  but 
liable  to  peel.  One  gallon  of  zinc  paint  contains  9.5  pounds  of 
zinc  oxide  and  5.7  pounds  of  oil  weighing  15.2  pounds. 

RED  LEAD. 

Red  oxide  of  lead  minium  is  made  by  heating  lead  oxide 
(litharge)  to  600  degrees  F.  It  is  poisonous,  is  effected  by  sul- 
phur fumes,  and  is  therefore  unsuitable  where  smoke  and  fumes 
occur.  Red  lead  dries  very  fast  arid  must  be  mixed  by  hand  every 
day  as  required,  or  it  will  harden  in  the  keg  or  pail.  As  a  result 
of  rapid  drying,  it  is  less  permanent  than  other  paints,  and  it 
cracks,  permitting  water  to  enter.  When  used  as  a  first  coat,  it 
should  be  covered  with  upper  coats  of  other  paints.  Red  lead  is 
often  adulterated  with  chalk,  lime,  oxide  of  iron,  and  brick  dust. 
Twenty  pounds  of  red  lead  pigment,  mixed  with  5J  pounds  of 
linseed  oil,  makes  a  gallon  of  paint.  One  gallon  of  linseed  oil 
weighing  7J  pounds  should  therefore  contain  from  28  to  33 
pounds  of  pigment.  Some  manufacturers  make  ready  mixed  red 
lead  paint  which  does  not  harden  or  settle  in  the  case  or  pail, 
and  which  they  recommend  as  excellent  for  priming  coats  on  steel. 
Raw  linseed  oil  must  be  used  with  red  lead,  for  the  paint  itself  is 
a  rapid  drier.  A  paint  of  combined  red  lead  and  lampblack  is 
made  by  mixing  12  pounds  of  red  lead  and  10  ounces  of  lamp- 
black with  each  gallon  of  raw  linseed  oil,  the  pigments  being 
mixed  dry  before  adding  the  oil,  and  no  turpentine,  benzine  or 
driers  should  be  used. 

IRON  OXIDE. 

Iron  oxide,  either  alone  or  with  other  materials,  has  been  more 
used  for  metal  paint  than  any  other  pigment,  and  the  theory  that 
it  promotes  corrosion  is  incorrect.  There  are  three  common  oxides 
of  iron:  (1)  the  black  magnetic  oxide,  not  often  used  as  a  pig- 
ment; (2)  anhydrated  sesquioxide  of  iron,  or  red  hematite,  vary- 
ing in  color  from  dark  brown  to  bright  red;  and  (3)  the  hydrated 
sesquioxide  of  iron,  or  rust,  known  as  brown  hematite.  The  oxide 
of  iron  as  used  for  pigments  often  contains  from  40  to  70  per  cent 


PAINT  381 

of  clay,,  and  it  should  contain  very  little  hydrated  sesquioxide  of 
iron,  a  good  proportion  being  25  per  cent  anhydrated  sesquioxide 
of  iron  and  75  per  cent  clay.  The  objections  to  iron  oxide  paints 
are  that  the  pigments  contain  sulphur  and  phosphorus,  unless  the 
ore  has  been  roasted  to  drive  them  out,  and  the  sulphur  is  inju- 
rious to  the  iron.  The  paint  is  also  a  poor  protective  in  the  pres- 
ence of  salt  water.  All  paints  which  contain  more  than  5  per  cent 
of  carbonate  of  lime  are  said  to  be  attacked  and  disintegrated  by 
sulphur  fumes  from  burning  coal,  and  the  majority  of  iron  oxide 
paints  contain  more  than  this  amount.  Iron  oxide  paint  weighs 
12  to  14  pounds  per  gallon. 

DKIEKS. 

Driers  are  used  to  make  the  oil  or  vehicle  dry  more  rapidly, 
the  most  common  ones  being  zinc  sulphate,  acetate  of  lead,  litharge, 
red  lead,  and  binoxide  of  manganese.  Only  enough  are  needed  to 
make  the  paint  harden.  Liquid  driers  are  sold  in  such  strength 
that  5  to  1.0  per  cent  added  to  raw  oil  paints  makes  them  dry  in 
twelve  to  twenty-four  hours,  but  more  than  10  per  cent  should  not 
be  used.  None  are  needed  when  painters'  boiled  oil  is  used  which 
contains  driers,  but  when  raw  oil  is  used  for  thinning,  they  are 
necessary  because,  unaided,  one  or  two  weeks  will  be  required  to 
harden  them.  Hardening  should  not  be  forced  by  excessive  driers 
or  heat,  for  the  paint  film  is  then  liable  to  crack.  Structural  steel 
paint  should  contain  no  liquid  driers,  neither  turpentine,  benzine 
nor  thinner,  for  such  additions  to  oil  lessen  its  permanence. 

SOLVENTS. 

Spirits  of  turpentine  is  the  principal  solvent.  It  is  a  volatile 
oil  distilled  from  the  turpentine  gum  of  pine  trees,  and  is  a  limpid 
and  colorless  liquid  with  a  strong  odor.  It  weighs  7  pounds  per 
gallon,  and  dries  in  twenty-four  hours.  When  spirits  of  turpen- 
tine is  used  without  oil,  the  resulting  paint  surface  has  a  dull 
finish.  Little  or  no  turpentine  should  be  used  on  surfaces  exposed 
to  weather.  Benzine,  which  is  a  mineral  oil  weighing  6.1  pounds 
per  gallon,  is  sometimes  used  instead  of  turpentine.  The  market 
price  of  turpentine  is  40  cents  per  gallon. 

STAINEES. 

If  the  desired  finish  color  is  different  from  the  base,  other  pig- 
ments must  be  added,  which  are  called  stainers.  The  principal 
ones  are  as  follows : 

Browns  are  mostly  iron  oxides,  and  include  burnt  umber  and 


382  MILL  BUILDINGS 

burnt  sienna,  from  Umbria  and  Sienna,  in  Italy,  and  Spanish 
brown. 

Reds  include  Indian  red,  which  is  ground  hematite  ore;  Vene- 
tian red,  made  by  heating  ochres;  vermilion  or  sulphide  of  mer- 
cury, Chinese  red,  etc. 

Blacks  are  mostly  carbons  in  some  form,  and  include  lamp- 
black, ivory  black  and  bone  black,  which  are  soots  from  burning 
these  substances. 

Blues  are  Prussian  blue  or  prussiate  of  potash;  cobalt  blue, 
made  by  roasting  cobalt  ore;  blue  ochre,  blue  lead,  and  indigo 
blue,  made  from  plants. 

Yellows  include  chrome  yellow,  yellow  ochre  or  clay  colored 
with  iron.,  and  raw  sienna,  which -is  clay  colored  with  manganese. 

Greens  are  made  by  mixing  yellow  and  blue,  the  most  perma- 
nent ones  being  made  from  copper  and  arsenic. 

JAPANS. 

Japan,  when  properly  applied,  is  the  best  known  protective  for 
metal  surfaces.  Black  japan  is  made  of  asphalt,  linseed  oil  and 
copal  rosin,  usually  Kauri  thinned  with  turpentine,  and  is  the 
familiar  coating  on  door  locks  and  hinges  with  a  smooth  black 
polish.  The  metal  is  dipped  in  japan,  and  then  baked  for  several 
hours  in  an  oven.  The  more  linseed  oil  and  the  less  drier  that 
it  contains,  the  more  durable  will  the  coating  be,  but  to  make  the 
coating  harder  when  baked,  extra  drier  is  often  added.  It  was 
formerly  used  for  small  articles  only,  but  investigations  now  under 
way  show  that  it  may  soon  be  applied  to  large  surfaces.  Japan 
can  only  be  applied  in  the  shop,  but  when  this  coat  is  effective, 
latex  ones  are  not  necessary.  The  duration  of  steel  structures 
with  ordinary  paint  protection  does  not  usually  exceed  twenty-five 
to  fifty  years,  and  when  considering  that  the  same  structures  would 
last  indefinitely  if  protected  with  such  a  coating  as  japan,  the 
extra  expense  would  be  ultimate  economy.  Up  to  the  present 
time,  however,  the  process  of  application  is  not  sufficiently  devel- 
oped to  make  its  use  practical  for  structural  steel  work. 

VARNISHES. 

Varnish  is  made  by  dissolving  gum  or  resin  in  oil,  turpentine 
or  alcohol,  the  gum  acting  like  the  base  in  paint.  When  the  vehi- 
cle dries  or  evaporates,  it  leaves  a  smooth,  solid  and  transparent 
film  of  resin.  Linseed  oil  should  be  used  as  the  vehicle  for  out- 
door or  exposed  work,  but  turpentine  at  a  less  cost  is  sometimes 


PAINT  383 

used  for  inside  surfaces.  The  quality  of  the  varnish  is  determined 
by  the  amount  of  gloss,  and  is  best  with  linseed  oil.  The  interiors 
of  power  houses  which  contain  expensive  machinery  are  frequently 
varnished  and  finished  as  a  show  place  for  visitors. 

Steel  floor  channels  under  the  wood  block  pavement  on  the 
Williamsburg  bridge  at  New  York,  after  being  washed  and  pickled 
in  dilute  acid,  were  dipped  in  hot  varnish  enamel  and  then  put  in 
ovens  and  baked  at  a  temperature  of  400  degrees  F.  For  two  or 
three  weeks  after  being  placed,  six  or  eight  hundred  workmen 
with  wheelbarrows  walked  daily  over  the  enameled  metal  without 
injuring  the  surface. 

SPECIAL  STEEL  PAINTS. 

There  are  many  excellent  prepared  paints  for  steel,  but  also 
many  worthless  makes,  and  as  some  paint  makers  recommend  their 
products  for  all  conditions,  care  should  be  taken  in  selecting  them. 
It  is  better  to  accept  the  judgment  of  an  engineer  or  architect, 
or  some  other  competent  and  disinterested  person. 

Steel  paints  are  made  of  linseed  oil,  asphalt,  tar  and  varnish, 
the  oil  paints  having  pigments  of  lead,  zinc,  iron  oxides,  carbon, 
lampblack  or  graphite.  For  ordinary  structural  work,  oil  paints 
are  the  best.  Sheet  metal  should  have  a  priming  coat  of  red 
lead,  covered  with  later  coats  of  iron  oxide  or  carbon,  prepara- 
tions of  tar  being  avoided.  Corrugated  iron  or  other  metal 
sheathing  should  receive  only  one  shop  coat,  for  if  painted  two 
coats  the  sheets  will  stick  together,  and  the  paint  peel  off.  Steel 
in  foundations  or  other  damp  places  exposed  continually  to  mois- 
ture or  condensation  should  be  coated  with  asphalt  paint  or  varnish. 

PRINCE'S  METALLIC  PAINT. 

This  is  made  from  blue  magnetic  iron  ore,  mined  in  Carbon 
County,  Pennsylvania,  and  contains  50  per  cent  of  iron  peroxide, 
25  per  cent  of  limestone  and  25  per  cent  of  sulphur.  The  ore  is 
broken,  roasted  and  ground  to  a  fine  powder,  in  which  form  it  is 
sold  at  $20  to  $40  per  ton.  The  roasting  reduces  its  weight  by 
one-third.  One  gallon  of  linseed  oil  mixed  with  7-|  pounds  of 
pigment,  after  standing  twelve  hours,  measures  1.2  gallons  of 
paint.  It  is  made  in  one  color  only — a  reddish  brown.  The  com- 
position and  cost  of  the  mixed  paint  per  gallon  is  as  follows : 

6^4  Ibs.  mineral,  at     1%  cents  per  Ib $  .09% 

6!,4  Ibs.  raw  oil  at  90       cents  per  gal 56 

Labor  in  applying 1.00 

Total  cost  per  gal.  applied $1.66% 


384  MILL  BUILDINGS 

One  gallon  covers  700  square  feet,  and  costs  22  cents  per  square 
for  one  coat  applied. 

ASPHALT  PAINT. 

Asphalt  is  a  substance  midway  between  coal  and  oil,  and  is 
composed  chiefly  of  carbon.  It  dissolves  in  linseed  oil,  is  very 
adhesive  to  wood  or  metal,  and  has  a  good  covering  capacity. 
Asphalt  paint  is  made  by  dissolving  the  asphalt  in  paraffin,  petro- 
leum naphtha,  or  benzine,  and  after  applying  the  mixture,  the 
volatile  oils  evaporate,  leaving  a  coating  of  asphalt.  It  is  applied 
hot  at  a  temperature  of  300  to  400  degrees  F.,  preferably  on  a  hot 
surface,  and  costs  80  cents  to  $1  per  gallon.  Steel  waterproof 
floors  are  frequently  covered  with  asphalt  one  inch  thick. 

DURABLE  METAL  COATING. 

This  is  a  black  asphalt  varnish,  made  by  Edward  Smith  and 
Company,  and  composed  of  asphaltum,  linseed  oil,  turpentine, 
and  Kauri  gum,  without  pigments.  It  is  sold  in  liquid  form 
ready  for  use,  and  requires  neither  thickening  nor  stirring,  though 
in  cold  weather  it  is  more  easily  applied  when  heated.  It  is  said 
to  contain  neither  tar,  naphtha  nor  benzine,  and  dries  slowly  by 
oxidation,  requiring  not  less  than  thirty-six  hours  for  the  first 
coat  and  a  week  for  complete  hardening.  One  gallon  will  cover 
400  square  feet,  and  it  costs  $1.50  to  $1.70  per  gallon,  by  the  barrel. 

P.   &  B.   PAINT. 

This  is  a  black  paint,  composed  of  asphaltum  dissolved  in 
bisulphide  of  carbon,  made  by  The  Standard  Paint  Company.  It 
has  a,  volatile  vehicle  which  dries  immediately  when  applied,  leav- 
ing a  coating  somewhat  similar  to  japan.  It  is  sold  in  liquid  form 
ready  for  use,  contains  no  tar  or  oil,  and  when  applied  dries  quickly. 
It  is  made  in  three  thicknesses;  a  gallon  of  the  first  covers  250 
square  feet  and  costs  $1.20,  while  one  gallon  of  the  thickest  covers 
only  100  square  feet,  and  costs  $1  per  gallon.  This  paint  is  elastic 
and  can  be  used  on  brick  or  concrete  as  well  as'  steel. 

COAL  TAB  PAINT. 

A  very  cheap  paint,  which  may  sometimes  be  satisfactory,  is 
made  by  mixing  eight  parts,  by  volume,  of  coal  tar  with  one  to 
two  parts  of  Portland  cement  and  one  to  one  and  one-half  parts 
of  kerosene  oil.  The  kerosene  oil  and  cement  are  first  mixed  to 
a  thin  cream  and  then  poured  into  the  tar.  As  tar  has  but  little 
value,  and  is  often  burned  for  fuel,  the  resulting  paint  costs  not 


PAINT  385 

over  10  to  15  cents  per  gallon.  It  adheres  well  to  black  and  to 
galvanized  surfaces,  and  when  the  kerosene  dries  it  leaves  a  coat- 
ing of  cement  and  tar.  This  paint  is  used  for  coating  steel  work 
at  the  United  States  Navy  Yards. 

Similar  mixtures  are  made  by  using  benzine  instead  of  kero- 
sene, and  chalk  or  lime  instead  of  cement.  It  is  a  good  wood 
preservative,  but  is  inflammable  and  is  a  common  and  inferior 
substitute  for  asphalt  paint. 

CARBONIZING   COATING. 

This  is  an  excellent  coating  for  steel,  composed  of  carbon  and 
oxide  of  lead  bases,  and  linseed  oil  without  volatile  oils  or  driers.  It 
has  great  adhesion  to  steel,  is  not  affected  by  sulphur  fumes,  and 
gives  protection  for  10  to  15  years  without  renewal.  One  gallon  of 
paint  is  required  for  every  5  or  6  tons  of  steel  work.  It  costs  $1.50 
to  $1.70  per  gallon  and  spreads  over  1.500  square  feet,  or  twice  the 
usual  spreading  area  of  paint. 

GRAPHITE  PAINT. 

Natural  graphite  is  found  in  Canada,  Mexico,  Ceylon,  and  in 
several  localities  in  the  United  States,  the  Canadian  graphite  being 
considered  the  best.  It  occurs  in  two  forms,  granular  and  foliated, 
the  former  being  best  suited  for  paint  making.  It  is  the  lightest 
pigment  known,  and  is  permanent  and  flexible.  The  kind  found 
in  northern  Michigan,  known  as  Superior  graphite,  contains  from 
10  to  90  per  cent  of  foreign  matter,  mostly  silicates  and  iron  oxides. 
Another  pigment,  known  as  "electric  graphite,"  is  made  by  heat- 
ing anthracite  coal  in  an  electric  furnace,  the  product  being  90 
per  cent  carbon. 

Graphite  paint  is  made  by  mixing  the  pigment  with  boiled  lin- 
seed oil,  to  which  is  added  a  small  amount  of  manganese,  litharge 
or  red  lead.  Two  pounds  of  dry  graphite  with  one  gallon  of  oil 
make  a  gallon  of  paint  weighing  9  pounds.  It  dries  slowly  as  com- 
pared with  other  paints,  for  one  gallon  of  linseed  oil  will  take  20 
pounds  of  red  lead,  but  not  more  than  2  pounds  of  graphite. 

CEMENT  COATING. 

Cement  coating  as  a  substitute  for  paint  is  made  by  mixing 
materials  in  the  following  proportion  by  weight.  Pure  red  lead  12 
parts,  Portland  cement  32  parts,  linseed  oil  4  parts,  and  drier  2  parts. 
This  is  mixed  to  a  paste,  like  putty,  and  applied  to  the  clean  metal 
surface  with  a  trowel,  being  laid  -/«  to  ^  inch  thick.  The  process 


386  MILL  BUILDINGS 

in  detail  is  as  follows:  First  clean  the  metal  surface  thoroughly; 
then  apply  a  coat  of  red  lead  paint  and  allow  it  to  set;  after  this 
apply  a  heavy  coat  of  japan  drier  and  spread  the  cement  paste  over 
the  drier  while  it  is  green.  The  japan  drier  must  not  he  allowed 
to  dry  before  the  paste  is  applied.  After  the  cement  has  hardened, 
it  should  be  given  a  final  coat  of  red  lead  paint.  The  coating 
described  takes  three  times  as  long  to  apply  as  ordinary  paint,  and 
costs,  including  cleaning  material  and  labor,  8  cents  per  square 
foot,  but  it  protects  metal  exposed  to  sulphur  and  fumes,  particu- 
larly the  fumes  and  blast  from  locomotive  stacks,  and  lasts  four 
times  longer  than  ordinary  paint.  If  an  engine  stack  is  within  2 
or  3  feet  of  the  coated  metal,  the  blast  may  be  so  severe  as  to 
require  a  protection  of  sheathing  boards  to  prevent  the  cement 
from  breaking.  Cement  mortar  without  oil  or  lead  lacks  elasticity 
and  is  easily  cracked  or  broken. 

COMPARATIVE  MERITS  OF  STEEL  PAINTS. 
Experiments  made  when  painting  steel  work  of  the  elevated 
railway  at  Harlem,  New  York,  with  seventeen  different  kinds  of 
paint,  showed  red  lead,  iron  oxides,  carbon  and  graphite  to  be  about 
equal,  with  slight  preference  for  the  last  two.  Thick  coats  are 
preferable  to  thin  ones,  and  large  spread  capacity  is  therefore  no 
advantage,  for  any  kind  of  paint  may  be  made  to  spread  by  adding 
thinners.  Red  lead  is  an  excellent  preservative,  and  is  suitable  for 
priming  coats,  but  when  exposed  to  gas  or  sulphur  must  be  cov- 
ered with  other  paint  as  an  external  protection.  Lead  and  iron 
oxides  combine  chemically  with  linseed  oil,  while  carbon  and  graph- 
ite do  not  combine,  but  simply  mix.  Silica  protects  as  well  as  any 
other  pigment,  but  when  used  alone,  is  hard  to  spread  and  drags 
under  the  brush;  but  graphite  mixed  with  it  acts  as  a  lubricant. 
Carbon  and  asphalt  can  be  ground  very  fine,  and  are  neutral. 

PAINT  FOR  WOODWORK. 

The  woodwork  on  the  exterior  of  shop  buildings  should  be  pre- 
served by  painting,  and  interior  woodwork  painted,  oiled  or  var- 
nished; very  little  turpentine  should  be  used  on  exterior  surfaces. 
The  first  or  priming  coat  may  be  clear  oil,  or  thin  paint  made  by 
adding  an  equal  volume  of  raw  linseed  oil  to  the  regular  mixture. 
A  gallon  of  paint  will  cover  only  half  as  much  area  on  the  first 
coat  as  on  later  ones,  because  the  bare  wood  surface  absorbs  the 
oil.  The  first  or  priming  coat  should  be  colored,  and  if  the  final 
one  is  white,  each  succeeding  coat  should  be  lighter  than  the  pre- 


PAINT  387 

vious  one.    Turpentine  may  be  used  in  intermediate  coats,  but  not 
in  the  first  nor  the  final  one. 

A  cheap  oil  finish  or  varnish  is  made  from  common  rosin,  lin- 
seed oil  and  benzine,  the  surface  being  rubbed  or  sandpapered 
between  successive  coats.  Shop  interiors  are  better  lighted  when 
they  are  painted  a  dark  shade  to  a  height  of  only  a  few  feet  above 
the  floor,  and  the  remaining  surfaces  white  or  a  light  color. 

PAINT  FOE  BRICK  OR  CEMENT  WALLS. 

Brick  and  concrete  absorb  moisture  and  are  therefore  improved 
by  waterproofing,  and  the  flat  color  effect  of  concrete  walls  is 
relieved  by  painting.  An  oil  paint  suitable  for  walls  is  made  by 
mixing  one  part  each  of  white  sand  and  quicklime  with  two  parts 
of  wood  ashes,  the  whole  being  passed  through  a  fine  screen.  To 
this  mixture  as  a  base,  enough  raw  linseed  oil  may  be  added  to 
make  a  thin  paint  which  can  be  applied  with  a  brush.  If  color  is 
desired,  it  is  added  to  the  oil  before  mixing  with  the  base. 

Another  oil  paint  for  walls  is  made  by  mixing  100  pounds  of 
clean  sand,  100  pounds  of  white  lead,  20  quarts  of  raw  linseed 
oil,  4  pounds  of  raw  umber,  1  pound  of  drier  and  1  pint  of  tur- 
pentine. When  mixed  to  proper  consistency,  it  can  be  applied  with 
a  large  brush. 

An  oil  wall  paint  known  as  Bay  State  Brick  and  Cement  Coat- 
ing has  a  cement  base  mixed  with  volatile  oil,  which  evaporates. 
It  contains  no  lead,  glue  or  water,  and  is  made  in  white  or  colors. 
It  can  be  applied  to  a  damp  surface,  will  not  absorb  water,  dries 
with  a  dull  finish,  and  may  be  scrubbed  to  remove  dirt.  It  is  made 
only  in  liquid  form,  ready  for  use,  and  never  in  paste. 

COLD  WATER  PAINT. 

Cold  water  paints  cost  much  less  than  oil  paint,  and  for  some 
purposes  are  quite  as  effective.  They  are  sold  in  the  form  of  pow- 
der, costing  6  to  10  cents  per  pound,  and  after  mixing  are  applied 
with  a  kalsomine  brush.  Five  pounds  of  powder  make  one  gallon 
of  cold  water  paint  and  cover  from  300  to  400  square  feet  of  first 
coat  on  smooth  boards,  and  150  to  200  square  feet  on  rough  boards, 
brick  or  concrete.  Two  good  makes  are  Magnite,  made  by  J.  A. 
and  W.  Bird  and  Company,  Boston,  and  Asbestine,  made  by  Johns- 
Manville  Company. 

A  good  cold  water  paint  is  made  by  mixing  one  bushel  of  lime, 
two  bushels  of  Portland  cement,  half  a  bushel  of  white  sand,  and  a 
barrel  of  water,  and  adding  6  pounds  of  sulphate  of  zinc  pre- 


388  MILL  BUILDINGS 

viously  dissolved  in  water:  It  must  be  well  mixed  to  the  consist- 
ency of  paint,  and  applied  with  a  whitewash  brush.  Coloring  may 
be  added  if  desired. 

WHITEWASH. 

Whitewash  is  pure  white  lime  mixed  with  water  and  it  adheres 
better  when  applied  hot.  It  is  easily  washed  off  by  rain  and  needs 
frequent  renewals.  The  wash  may  be  hardened  to  prevent  cracking 
by  adding  to  each  bushel  of  lime  1  pound  of  salt  and  2  pounds  of 
zinc  sulphate.  It  may  be  tinted  by  adding  to  each  bushel  of  lime, 
4  to  6  pounds  of  ochre  for  cream  color,  6  to  8  pounds  of  raw  umber 
and  3  to  4  pounds  of  lamp  black  for  buff  or  stone  color,  and  6  to  8 
pounds  of  umber,  2  pounds  of  Indian  red  and  2  pounds  of  lamp 
black  for  fawn  color. 

KALSOMINE. 

This  wash  is  made  of  Paris  white,  glue  and  water,  colored  as 
desired,  and  applied  with  a  brush.  One  gallon  covers  150  square 
feet,  and  one  coat  of  sizing  and  one  of  kalsomine  costs  60  to  80 
cents  per  square. 


CHAPTER  XXXVII. 

PAINTING. 

Painting  is  for  the  purpose  of  preserving  structural  materials 
and  beautifying  or  decorating  them.  Shop  interiors  are  painted 
white  to  increase  the  inside  lighting  and  give  them  a  cleaner 
appearance. 

PRESERVATION  OF  MATERIALS. 

The  amount  of  money  being  invested  in  modern  shops  is  so 
large  that  the  preservation  of  the  wood,  concrete  and  steel  of 
which  they  are  built  is  an  important  matter.  Steel  and  iron,  which 
are  replacing  wood  for  framing  and  covering,  are  susceptible  to 
rust,  and  aluminum,  copper  and  other  non-rusting  metals  are 
too  expensive  for  structural  purposes.  Thin  metal  sheathing  for 
walls  and  roofs  must  be  painted  and  protected,  or  it  will  be  rusted 
through  in  two  or  three  years.  Many  steel  structures,  especially 
some  near  the  sea  coast,  built  less  than  twenty  years  ago,  are  already 
so  damaged  by  rust  and  corrosion  that  they  must  either  be  cleaned 
by  sand  blast  and  repainted,  or  replaced  by  new  ones,  before  another 
decade.  Steel  work  exposed  to  salt  water  spray,  or  in  damp  places 
under  ground,  is  especially  in  danger,  and  should  be  well  protected ; 
wherever  possible,  the  covering  or  fireproofmg  should  be  removable 
in  places  for  inspection.  Some  of  the  greatest  bridges  are  already 
so  badly  injured  with  rust  that  before  many  years  parts  of  them 
near  the  water  must  either  be  strengthened  or  replaced  with  new 
material,  notwithstanding  the  constant  service  of  painters  employed 
upon  them.  The  paint  used  on  the  steel  framing  in  the  New  York 
subway  is  now  peeling  off  to  such  an  extent  as  to  prove  it  useless 
in  damp  places  underground. 

Up  to  the  present  time,  the  preservation  of  materials,  especially 
of  iron  and  steel,  has  not  received  the  attention  that  it  deserves. 
There  is  little  agreement  or  uniformity  of  specifications,  the  de- 
signer either  using  his  favorite  paint  or  permitting  the  contractor 
to  apply  whatever  he  may  choose.  Structural  steel  is  often  exposed 
to  the  weather  for  a  year  or  more  without  oil  or  paint,  and  is  then 
used  for  building  purposes  without  cleaning,  the  rust  being  covered 
with  a  coat  of  paint.  Framing  made  of  such  material  must  be  of 
short  duration. 

389 


390  MILL  BUILDINGS 

Rust  is  the  result  of  oxygen  from  water  or  moisture  uniting 
with  iron  to  form  hydrated  oxide  of  iron.  It  starts  beneath  the 
paint,  and  as  rust  occupies  twice  the  volume  of  the  iron  which  it 
contains,  it  loosens  the  paint  and  the  latter  falls  off,  leaving  the 
metal  exposed.  Eust  absorbs  24  per  cent  of  its  own  weight  of  mois- 
ture, but  if  oxygen,  carbonic  acid  gas  and  moisture  are  kept  away, 
iron  cannot  rust. 

METHODS  OF  PRESERVATION. 

Metal  is  preserved  by  covering  it  with  an  impervious  film  of 
paint  or  enamel,  by  galvanizing  or  coating  with  zinc  or  lead,  and 
by  imbedding  it  in  cement  concrete,  or  coating  the  surface  with 
cement  mortar.  Methods  of  producing  a  non-oxidizable  surface 
on  iron  or  steel,  by  electric  treatment,  are  described  in  Kent's 
Mechanical  Engineer's  Pocket  Book,  but  are  not  in  general  use. 

CLEANING. 

It  is  very  important  that  metal  surfaces  be  cleaned  before  paint 
is  applied.  The  benefit  from  painting  depends  more  on  having  a 
clean  surface  than  on  the  quality  of  the  paint  or  on  any  other 
consideration.  Poor  paint  on  a  clean  surface  is  better  than  the  best 
and  most  expensive  paint  on  a  rusty  surface.  Applied  on  a  wet 
surface  over  rust,  scale  and  grease,  no  paint,  however  good,  will 
preserve  the  metal,  for  it  will  peel  off  and  the  expense  is  wasted. 

Mill  scale  is  the  first  coating  that  must  be  removed.  It  does 
not  loosen  immediately  after  rolling,  but  must  be  dislodged  with 
scraper  or  stiff  wire  brush  (cost,  $4  per  dozen).  Grease  and  dirt 
can  be  washed  off,  or  removed  by  pickling  in  dilute  acid,  and  rust, 
with  a  steel  scraper  and  sand  blast.  Galvanized  sheet  iron  and  tin 
smeared  with  grease  and  chemicals  used  in  coating  them  can  be 
cleaned  by  washing  with  soap  and  water  or  with  benzine.  After 
washing,  the  plate  must  be  wiped  with  cotton  or  waste  to  remove 
the  grease,  for  should  it  remain,  it  will  spread  in  a  thinner  layer, 
and  dry  as  the  benzine  evaporates.  Deep-seated  rust  spots  can  be 
removed  with  a  painter's  gasoline-burning  torch  (Fig.  627),  which 
converts  the  rust  into  peroxide  of  iron,  and  it  can  then  be  brushed 
off.  Old  paint  and  varnish  can  be  scraped  or  burnt  from  the 
surface. 

PICKLING. 

A  method  of  cleaning  steel  work  prior  to  painting  is  as  follows : 
First  wash  the  metal  in  10  per  cent  solution  of  caustic  alkali  or  soda 
to  remove  grease,  and  then  dip  in  boiling  water  to  remove  the  alkali, 
after  which  the  metal  is  put  in  a  hot  10  to  20  per  cent  solution  of 


PAINTING 


391 


sulphuric  acid,  allowing  it  to  remain  until  all  rust  is  gone,  usually 
5  to  15  minutes;  weaker  acid  takes  a  longer  time  to  act.  The  metal 
is  then  taken  out  of  the  acid  and  washed  with  hose  and  water  jet 
under  a  pressure  of  100  pounds  to  the  square  inch.  The  acid  must 
be  completely  removed  or  more  harm  than  good  is  done  by  the 
operation.  To  insure  neutralization  of  any  remaining  acid,  after 
the  metal  is  washed  with  clean  water,  it  should  be  placed  in  a  hot 
10  per  cent  solution  of  carbonate  of  lime  or  soda  and  again  washed, 
after  which  it  is  put  in  a  drying  oven.  The  whole  process  of 
pickling  costs  from  50  cents  to  $1  per  ton  of  steel  work,  depending 
on  the  facilities  for  doing  the  work  and  the  cost  of  transferring 
the  pieces  from  the  riveting  to  the  pickling  shop  and  back  again. 

SAND    BLAST    CLEANING. 

This  is  the  most  effective  way  of  cleaning  steel  that  is  coated 
with  scale,  rust  or  oil  paint,  the  only  objection  to  it  being  the  cost 


Fig.  627. 


Fig.  628. 


and  the  extra  time  required.  The  equipment  consists  of  one  or 
more  air  compressors,  capable  of  delivering  250  cubic  feet  per 
minute  for  each  nozzle,  driven  with  electric  motor  or  engine,  and 
a  sand  and  air  tank,  with  2^-inch  rubber  hose  and  metal  nozzles 
(Fig.  628).  Portable  air  compressors  are  preferable  for  field 
cleaning.  The  tank  is  kept  under  pressure  of  20  to  25  pounds  per 
square  inch,  producing  a  velocity  of  sand  and  air  at  the  nozzle  of 
300  feet  per  second.  Nozzles  of  -|  inch  diameter  are  used,  which 
are  soon  worn  to  f  inch  or  more.  The  sand  should  be  coarse  and 


392  MILL  BUILDINGS 

dry,  and  can  be  used  three  or  four  times  before  being  discarded. 
One  cubic  foot  of  sand  is  required  for  every  3  square  feet  of  surface 
cleaned,  and  10  cubic  feet  of  sand  per  ton  of  steel.  The  nozzles 
are  held  6  or  8  inches  from  the  surface  and  the  operators  have  hel- 
mets with  glass  fronts,  to  protect  their  eyes  and  lungs.  The  sand 
blast  leaves  the  surface  clean  and  dry,  but  as  a  thin  film  of  rust 
forms  immediately,  the  cleaned  surface  must  be  painted  within  two 
or  three  hours.  The  practice  is  to  spend  the  first  six  hours  of  each 
day  in  cleaning,  and  the  remaining  hours  in  repainting  this 
surface. 

One  man  can  clean  80  square  feet  of  old  painted  work  per  hour 
at  a  cost  for  labor  and  material  of  3  cents  per  square  foot.  Clean- 
ing new  steel  at  the  shop,  coated  only  with  light  rust  and  mill  scale, 
costs  J  cent  per  square  foot,  or  $1  to  $2  per  ton. 

Sand  blast  cleaning  of  50,000  square  feet  of  steel  framing  for 
the  elevated  railroad  at  Harlem,  New  York,  cost,  under  experi- 
mental conditions,  10  to  15  cents  per  square  foot,  but  could  be 
repeated  for  half  that  amount.  The  steel  had  been  painted  with 
four  coats,  and  12  tons  of  old  paint,  rust  and  scale  was  removed  at 
a  cost  of  $10,000,  not  including  repainting.  The  cost  of  sand 
blast  cleaning  the  steel  coal  pockets  at  the  Key  West  Naval  Station, 
including  labor,  material  and  machine  painting  with  tar  and 
cement,  was  4.4  cents  per  square  foot. 

MAKING  AND   APPLYING   PAINT. 

Paint  is  sold  in  cans  or  barrels,  mixed  and  ready  for  use,  or 
as  a  paste  in  25,  50  and  100  pound  kegs,  which  needs  thinning  and 
stirring,  and  pigments  are  sold  in  powdered  form.  Paste  is  thinned 
by  adding,  to  every  10  pounds,  three  or  four  pints  of  oil.  The  best 
mixing  is  done  in  a  machine,  but  red  lead,  because  of  its  rapid  dry- 
ing, must  be  mixed  by  hand  as  required  for  use. 

The  proportion  of  ingredients  depends  on  the  surface  to  which 
the  "paint  will  be  applied,  whether  wood,  concrete  or  metal,  and 
whether  rough  or  smooth,  a  porous  surface  needing  more  oil  than 
an  impervious  one.  Turpentine  is  sometimes  added  to  paint  for 
exterior  surfaces  exposed  to  the  sun,  to  prevent  it  from  blistering, 
and  also  over  old  work  to  make  the  new  paint  adhere. 

The  colors  on  manufacturing  baildings  are  selected  more  for 
utility  than  for  decorative  effects,  though  in  some  cases  the  latter 
are  desirable.  The  interior  of  large  pumping  stations  or  power 
houses  containing  valuable  machinery  is  frequently  finished  to 
harmonize  with  the  excellence  of  the  machines.  Such  walls  are 


PAINTING  393 

often  lined  with  enameled  brick,  or  painted  a  light  color  and  enam- 
eled. Inside  lighting  is  increased  from  25  to  50  per  cent  by  light- 
colored  interior  walls  and  roofs.  The  best  practice  is  as  noted 
under  "Painting  for  Woodwork."  Light  colors  are  made  with 
bases  of  zinc  or  lead,  and  when  such  a  finish  is  desired  on  steel,  the 
first  and  second  coats  should  be  dark  preservative  paints.  It  is 
convenient  for  inspection  to  specify  that  successive  coats  shall  be  of 
slightly  different  colors,  for  it  is  then  easier  to  see  what  parts  have 
been  painted  and  there  is  less  chance  of  missing  parts  of  any  coat. 
As  the  best  preservative  paints  are  black,  colors  are  secured  at  a 
slight  sacrifice  of  permanence. 

Paint  is  applied  either  by  hand  brushes,  by  compressed  air 
machines,  or  by  dipping.  Dipping  is  suitable  only  for  shop  coats 
and  is  used  chiefly  for  bolts  and  other  small  parts,  though  some 
shops  use  emersion  for  large  riveted  sections,  leaving  the  metal  in 
hot  paint  for  about  15  minutes,  at  a  temperature  of  200  degrees  F. 
All  things  considered,  hand  painting  with  brushes  is  the  most 
satisfactory. 

AIR  BLAST  PAINTING. 

A  compressed  air  painting  machine  consists  of  a  tank  for  100 
pound  pressure,  supplied  with  air  by  means  of  a  hand  pump,  and 

rubber  hose  for  supply  and  discharge. 
(Fig.  629).  Each  machine  is  provided 
with  a  spray  pipe,  cock  and  nozzle,  an 
extra  tip,  a  200-pound  pressure  gage, 
galvanized  sieve,  suction  and  discharge 
hose,  and  is  worked  by  two  men,  one  at 
the  pump  and  the  other  directing  the 
nozzle.  The  largest  size  machine,  cost- 
ing $40,  is  equal  to  the  work  of  thirty 
men  with  brushes,  while  the  smallest 
size,  costing  $25,  is  equal  to  the  work 
of  ten  men,  and  will  cover  800  square 
F.  feet  of  painted  surface  per  hour. 

Painting  coal  sheds  at  Key  West,  Flo- 
rida, with  cement  and  tar  paint,  put  on  with  air  machines,  showed 
that  each  gallon  of  paint  put  on  by  compressed  air  covered  145 
square  feet  of  surface.  Machine  painting  has  the  disadvantage  of 
conveying  moisture  and  air  to  the  surface,  is  wasteful,  and  soils 
the  floor  and  surroundings.  Hand  painting  with  brushes  is  there- 
fore generally  preferred. 


394  MILL  BUILDINGS 

SHOP    COATS. 

The  success  or  failure  of  painting  depends  upon  the  first  coat. 
If  it  is  applied  over  a  wet  or  greasy  surface,  coated  with  scale,  rust 
or  mud,  the  first  and  succeeding  coats  will  certainly  peel  off,  leav- 
ing the  metal  exposed.  The  first  coat  should  be  applied  on  the 
clear  grayish-white  metal  surface,  with  paint  or  metal  hot.  The 
paint  may  be  heated  by  suspending  pails  of  it  in  hot  water.  The 
permanence  of  mill  marks  on  steel  shows  the  benefit  of  applying 
paint  to  a  hot  surface,  for  it  then  spreads  better  and  adheres 
more  firmly.  Some  prefer  to  have  metal  oiled  at  the  rolling  mill 
while  it  is  hot  and  kept  under  cover  until  manufactured,  and  again 
oiled  or  painted  before  shipping.  The  disadvantage  in  this  is  that 
the  mill  scale  is  not  then  removed,  and  when  it  peels  brings  the 
oil  and  paint  with  it.  Others  do  not  even  oil  metal  until  after 
erection,  preferring  rust  to  mill  scale.  Days  with  the  proper  at- 
mospheric conditions  should  be  chosen  for  applying  the  first  coat. 
The  air  should  be  dry  and  clear,  so  dampness  or  dew  will  not 
form  on  the  surface  to  be  painted,  and  the  temperature  should  be 
50  degrees  F.  or  more.  Several  thin  coats  are  better  than  a  less 
number  of  thicker  ones,  for  pores  in  the  earlier  coats  will  be  filled 
by  succeeding  ones.  Each  coat  should  be  thoroughly  dry  before 
applying  another.  Column  bases  or  other  inaccessible  parts  should 
be  painted  before  setting.  Turpentine  is  often  added  by  the  work- 
men to  make  the  paint  thinner  and  easier  to  spread,  but  this  should 
be  avoided.  Rivet  heads,  projecting  points  and  edges  should  be 
given  a  second  partial  coat,  which  is  allowed  to  dry  before  the  final 
field  coats,  for  the  brush  drags  over  edges  and  projections,  leaving 
less  paint  than  on  flat  surfaces. 

TABLE  LXIII. 
PAINT. 

Iron  Eed  White  Graph-  Car- 
Pigment  and  oil —                 Oxide.  Lead.  Lead.  He.  Asphalt  fcon. 

Vol.  in  gals 2.6  1.4  1.7  2.               4 

Weight  in  Ibs 32.7  30.4  33.  20.5           30 

Lbs.  of  pigment 

per  gal.  of  oil 24.75  22.40  25.  12.50       17.25      

Sq.  ft.  covered  first  coat..   650.  700.  500.  600.  300.         1,000 

Sq.  ft.  covered  second  coat  700.  1,000.  700.  800.  500.         1,500 

Sq.  ft.  covered  two  coats.   375.  400.  300.  400.  250.            650 

Cost   per  gal $.53  $1.25  $     .85  $1.10  $     .40     $1.50 

Cost  100  sq.  ft.  first  coat         .10  .18  .17  .14  .13         .15 

Cost  100  sq.  ft.  second  coat         .07  .13  .12  .10  .08         .10 

The  covering  capacity  of  paint  is  frequently  exaggerated,  and 
depends  on  the  thickness  of  the  mixture  and  the  smoothness  of  the 
*  Prices  are  based  on  raw  linseed  oil  costing  60  cents  per  gal. 


PAINTING  395 

surface.  It  can  always  be  increased  by  the  addition  of  thinners, 
and  may  vary  50  per  cent  more  or  less  from  the  areas  given  in  the 
above  table. 

Light  structural  work  averages  250  square  feet,  and  heavy 
structural  work  150  square  feet  of  surface  for  every  ton  of  steel, 
and  in.  estimating  the  amount  of  paint  required  for  two  coats,  it  is 
customary  to  allow  one  gallon  for  every  ton  of  light  steel  work, 
and  half  a  gallon  for  every  ton  of  heavy  steel  work.  One  gallon 
of  tar  at  300  degrees  F.  covers  220  square  feet  of  surface.  The 
volume  of  mixed  paints  exceeds  that  of  oil  by  20  to  75  per  cent. 

COST   OF  PAINTING. 

The  cost  of  painting  is  made  up  of  two  factors:  (1)  cost  of 
materials,  and  (2  )cost  of  labor  in  applying  it.  The  cost  per  gal- 
lon of  several  kinds  of  paint  is  given  in  the  table  on  page  394,  and 
the  cost  of  applying  it  depends  (1)  on  the  rate  of  wages  paid  to 
workmen,  and  (2)  the  amount  of  surface  that  a  man  can  paint 
per  day.  A  table  of  wages  paid  to  laborers  and  painters  in  differ- 
ent parts  of  Xorth  America,  which  is  subject  to  change,  is  given 
on  page  420.  Laborers  receive  from  $1.25  to  $3  per  day,  and  paint- 
ers from  $2.75  to  $4.50  per  day.  Structural  paint  can  sometimes 
be  applied  by  common  laborers,  but  in  many  places  the  operation 
of  trade  unions  may  necessitate  employing  regular  painters  at  a 
higher  rate.  Generally  the  cost  of  applying  paint  is  two  to  three 
times  the  cost  of  the  materials.  From  80  to  90  per  cent  of  the 
total  cost  is  for  the  labor  and  the  linseed  oil.  Mixed  paint  that  is 
sold  at  a  less  price  per  gallon  than  the  cost  of  linseed  oil  cannot 
contain  pure  oil,  which  is  the  chief  essential  of  a  good  product. 
The  average  amount  of  surface  that  can  be  painted  by  a  man  in 
one  eight-hour  day  is  as  follows : 

First  coat  on  tin  or  metal  roofs 2,000  sq.  ft.  per  day 

First  coat  on  wood    buildings 1,000  sq.  ft.  per  day 

First  coat  on  structural  steel  300  to       500  sq.  ft.  per  day 

A  day's  work  on  second  or  subsequent  coats  is  80  per  cent  of 
the  amounts  given  above. 

The  cost  of  painting  steel  structural  work  with  three  coats  of 
graphite  at  $1.10  per  gallon,  one  coat  being  applied  at  the  shop 
and  the  other  two  after  erection,  with  shop  labor  at  $1.50  per  day, 
and  field  labor  at  $2.50  per  day,  is  as  follows : 


396  MILL  BUILDINGS 

COST  PEE  TON  OF  PAINTING  STRUCTUBAL  STEEL. 

One  shop  coat.  Heavy  work.  Light  work. 

Cost  of  paint  per  ton  of  steel $  .33  $  .55 

Cost  of  labor  per  ton  of  steel 15  .20 

Cost  per  ton  of  one  shop  coat $  .48  $  .75 

Two  coats  after  erection. 

Cost  of  paint  per  ton  of  steel    $  .47  $  .78 

Cost  of  labor  per  ton  of  steel 80  1.10 

Cost  per  ton  of  2  erection  coats $1.27  $1.88 

Total  cost  per  ton  of  3  coats $1.75  $2.63 

Generally,  one  shop  coat  of  graphite  paint  costs  50  to  75  cents 
per  ton  of  steel,  while  two  field  coats  cost  from  $1.25  to  $1.75  per 
ton.  Two  field  coats  of  iron  oxide  paint  will  cost  from  $1  to  $1.50 
per  ton.  Coating  with  tar  at  10  cents  per  gallon.,  and  labor  at 
$1.50  per  day,  costs  50  cents  per  ton  for  heavy  steel  work  to  80 
cents  per  ton  for  light  work. 

Present  union  prices  for  painting  woodwork  with  oil  paint  are 
as  follows : 

One  coat  work  $1.35  per  100  sq.  ft 

Two  coat  work   2.00  per  100  sq.  ft. 

Three   coat   work 2.75  per  100  sq.  ft. 

Cold  water  painting  by  compressed  air,  including  material  and 
labor,  costs  $1  per  100  square  feet. 


CHAPTER  XXXVIII. 

PAINTING  SPECIFICATIONS  FOR  STRUCTURAL  STEEL. 

1.  All  structural  iron  and  steel,  from  the  time  of  rolling  till 
it  is  oiled  or  painted,  shall  be  kept  under  cover  and  protected  from 
the  rain  and  weather. 

2.  It  shall  be  piled  on  skids,  and  care  taken  to  avoid  scraping 
or  injuring  oiled  or  painted  surfaces. 

3.  Steel  shall  never  be  laid  on  the  ground,  either  at  the  works 
or  at  the  building  site. 

4.  Corrugating  of   sheet  metal   shall  be   done   before   oil   or 
paint  is  applied. 

5.  All  metal  shall   receive  one  coat  of  either  linseed  oil  or 
paint  at  the  shop. 

6.  A  shop  coat  of  oil  (if  used)  shall  be  applied  to  the  struc- 
tural shapes  at  the  mill  while  the  metal  is  hot,  and  it  shall  then 
be  stored  under  cover  on  skids  till  needed  in  the  riveting  shop. 

QUALITY    OF    OIL   AND    PAINT. 

7.  Oil  shall  be  of  the  best  quality  of  raw  (or  boiled)  linseed 
oil,  chemically  and  commercially  pure.     Raw  oil  shall  contain  no 
turpentine,  benzine,  thinners  or  driers  of  any  kind. 

8.  Paint  shall  be  the  kind  specified.    Mixed  paint  is  preferred 
to  that  made  from  paste  or  powder. 

9.  All  linseed  oil  and  mixed  paint  shall  be  bought  direct  from 
the  manufacturers,  and  shall  be  delivered  at  the  works  or  building 
site  in  original  sealed  cases  or  barrels,  accompanied  with  a  signed 
certificate,  from  the  manufacturers,  of  the  number  of  cases  shipped, 
and  the  price  paid  for  same,  and  this  certificate  shall  be  delivered 
to  the  engineer  on  demand. 

10.  The  original  cases  shall  be  opened  in  the  presence  of  the 
engineer  or  owner  or  their  representative,  and  tested  if  desired. 

11.  Paint  shall  contain  no  thinner  of  any  kind,  and  turpen- 
tine or  benzine  shall  not  be  permitted  on  the  premises  for  any  pur- 
pose, excepting  with  written  permission  of  the  engineer,  and  then 
only  in  the  amount  specified. 

397 


398  MILL  BUILDINGS 

CLEANING. 

12.  All  metal,  before  assembling,  and  after  it  has  been  cut, 
punched  and  bored,  shall  be  thoroughly  cleaned,  and  all  rust,  loose 
scale,  mud,  dirt  and  grease  removed,  either  by  washing,  pickling, 
scrapers,  chisels,  wire  brushes,  or  the  sand  blast.     If  more  than 
light  surface  rust  exists,  it  shall  be  heated  with  a  burning  torch 
until  the  oxide  is  converted. 

13.  The   clear   grayish-white   surface   of   the   metal   shall   be 
exposed  before  oil  or  paint  is  applied. 

SUBFACES  IN   CONTACT. 

14.  Before  assembling,  all  surfaces  which  will  be  in  contact 
shall  be  thoroughly  cleaned  and  given  a  coat  of  paint  or  oil,  and 
all  small  cavities  which  will  be  inaccessible  after  riveting  shall  be 
filled  with  cement. 

SHOP  COAT. 

15.  All  surfaces,  before  painting,  shall  be  dusted  off  with  a 
bristle  brush,  cotton  cloth  or  waste. 

16.  Pins  and  turned  surfaces  shall  receive  a  coat  of  white  lead 
and  tallow. 

17.  All  other  surfaces  shall  receive  a  full  coat  of  linseed  oil 
or  paint,  applied  not  later  than  three  hours  after  the  surface  has 
been  cleaned. 

18.  Small  parts  such  as  loose  plates,  bolts,  rivets,  etc.,  shall  be 
dipped  in  the  liquid  oil  or  paint. 

19.  Painting  on  cars  will  not  be  permitted,  excepting  to  touch 
up  points  that  have  been  scraped  in  loading. 

20.  Shop  marks  shall  be  neatly  painted   and  compactly  ar- 
ranged, and  when  dry  they  shall  be  covered,  for  protection,  with  a 
coat  of  boiled  linseed  oil. 

APPLYING  PAINT. 

21.  Hand  painting  with  brushes  shall  be  preferred  to  machine 
painting. 

22.  Shop  painting  shall  generally  be  done  under  cover  in  a 
warm  atmosphere,  preferably  from  60  to  80  degrees  F.,  and  never 
out  of  doors  excepting  in  bright  sunshine. 

23.  The  paint  or  oil  shall  be  hot  when  applied,  and  the  metal 
shall  preferably  be  warm. 

24.  Paint  shall  be  well  spread  out  with  brushes  in  a  smooth 
and  even  coat,  well  worked  around  rivet  heads,  angles  and  corners. 

25.  All  surfaces,  before  painting,  shall  be  clean  and  dry  and 


PAINTING  399 

free  from  moisture,  and  no  painting  shall  be  done  in  damp,  freez- 
ing weather. 

26.  Paint  shall  be  thinned  by  heating  rather  than  with  tur- 
pentine. 

27.  Proper  facilities  shall  be  given  for  inspection,  which  shall 
be  done  only  by  the  engineer  or  his  agent. 

28.  When  steel  work  is  ready  for  painting,  the  inspector  shall 
be  notified,  and  no  painting  shall  be  done  until  the  surface  and  the 
weather  conditions  have  been  approved. 

29.  Brushes  shall  be  large  sized,  round  or  oval  bristle  brushes, 
2  or  2-|  inches  in  diameter.     Flat  brushes,  or  any  over  3J  inches 
wide,  will  not  be  permitted. 

SHIPPING. 

30.  Painted  material  shall  not  be  exposed  to  the  weather  until 
it  is  dry,  or  until  it  has  formed  a  good  initial  set,  and  shall  not 
be  loaded   on  cars  until   at  least  twenty-four  hours   after  being 
coated.    It  must  be  carefully  piled  and  arranged  so  the  painted  sur- 
face will  receive  the  least  possible  injury. 

FIELD  PAINTING. 

31.  After  erection,  steel  work  shall  be  inspected  and  cleaned 
from  mud,  dirt,  scale  and  rust.     Sheet  metal  shall,  if  necessary,  be 
washed  with  soap  and  water  or  benzine,  and  galvanized  iron  shall 
be  washed  or  allowed  to  weather  for  several  weeks,  before  painting. 

32.  Small  cavities  or  inaccessible  places  shall  be  filled  with 
cement,  and  all  rusty  spots  or  scratched  places,  corners,  projecting 
parts,  like  bolt  and  rivet  heads,  and  the  edges  of  angles,  shall  be 
given  a  partial  coat,  spread  1  or  2  inches  past  the  edges.     When 
this  partial  coat  is  dry,  the  entire  steel  work  shall  be  given  one 
or  two  complete  coats  of  paint,  with  at  least  five  days  intervening 
between  successive  applications. 

33.  All  coats  shall  preferably  be  of  a  slightly  different  color. 

34.  Surfaces  of  metal  sheathing  corrugated  iron  and  cornices, 
which  are  inaccessible  after  placing,  shall  be  given  a  second  coat 
before  erection. 

35.  All  field  coats  shall  be  done  by  skilled  labor. 

36.  If  light  colors  are  desired  for  the  final  coats,  the  steel 
shall  then  receive  two  coats  of  paint,  tinted  as  desired,  made  by 
mixing  equal  parts  by  weight  of  white  lead  and  zinc  oxide  with 
a  vehicle  composed  of  one  part  hard  varnish  rosin,  two  of  linseed 
oil  and  a  thinner. 

37.  Samples  of  the  proposed  paints  must  be  submitted  at  least 


400  MILL  BUILDINGS 

three  months  in  advance,  and  no  paint  shall  be  used  until  it  has 
been  accepted  and  approved,  but  the  paint  which  is  used  must  be 
the  same  as  the  sample  approved,  and  no  other. 

38.  If  the  shop  coat  c'onsists  of  oil,  the  steel  work  may  then 
be  allowed  to  remain  from  one  to  six  months  before  recoating,  and 
after  all  mill  scale  is  off,  it  shall  be  inspected,  cleaned  and  painted 
as  described  above. 

PAINTING  OF  OLD  WORK. 

39.  All  dirt,  dust,  scale  and  loose  paint  shall  first  be  removed, 
using  a  hot  blast  blow  torch,  or  sand  blast,  if  necessary. 

40.  Deep-seated  rust  spots,  not  accessible  to  a  scraper,  tool  or 
chisel,  shall  be  heated  with  a  burning  torch,  and  when  the  rust  is 
decomposed,  it  shall  be  removed  with  a  brush. 

PENALTY. 

41.  If  inspection  of  oil  or  paint  shows  it  to  be  different  or 
inferior  to  that  approved  and  specified,  the  contractor  shall  then 
pay  the  expense  of  testing,  and  shall  clean  off  and  remove  all  paint 
already   applied,   and   shall   repaint  the  surface  with   the  proper 
material,  without  extra  compensation. 


PART  V 

ENGINEERING  AND  DRAFTING  DEPARTMENTS 
OF  STRUCTURAL  WORKS 


CHAPTER  XXXIX. 
THE  EXGIXEERIXG  DEPARTMENT. 

INQUIETES. 

Inquiries  for  designs  and  estimates  on  steel  structures  are 
received  with  the  mail  in  the  general  office,,  and  referred  to  the 
engineering  department.  These  may  include,  besides  mill  build- 
ings, all  kinds  of  steel  cage  factory,  warehouse  and  office  build- 
ings, and  business  blocks  with  only  partial  frames.  There  may 
be  requests  also  for  designs  and  estimates  for  standpipes,  water 
towers,  floors,  platforms,  observation  stands  or  any  kind  of  plate 
and  bar  construction,  ordinarily  made  by  bridge  and  structural 
works.  Many  inquiries  are  received  from  architects  and  others 
who  are  seeking  information,  but  are  not  prospective  purchasers, 
and  the  officers  of  the  company  must  decide  to  what  extent  these 
will  receive  attention.  Companies  which  intend  retaining  the  good 
will  of  all  interested  in  their  business  will  probably  make  accommo- 
dation designs  and  estimates,  even  though  an  extra  estimator  be 
needed  for  this  purpose.  Other  companies  may  consider  the  expense 
unwarranted,  as  there  are  too  many  quotations  to  prospective  buyers 
to  permit  doing  accommodation  work.  Approximate  estimates  are 
usually  close  enough  for  this  purpose,  and  it  is  better  to  make 
them  than  decline  the  inquiries. 

Invitations  to  tender  on  construction  work  must  be  carefully 
considered  before  being  accepted.  The  work  may  be  too  large,  too 
small,  or  have  insufficient  financial  security,  or  the  chances  of 
securing  a  contract  may  be  too  remote  to  be  worth  the  labor.  The 
manager  and  engineer  must  decide  whether  or  not  it  is  best  to 
prepare  the  estimates. 

401 


402  MILL  BUILDINGS 

ORGANIZATION  AND  OFFICE. 

The  engineering  department  of  a  structural  works  will  com- 
prise a  chief  engineer  and  such  assistants  as  he  may  need,  depend- 
ing on  the  capacity  of  the  works  and  the  amount  of  estimating  that 
is  needed  to  keep  the  shops  supplied.  A  small  plant  can  be  kept 
busy  by  one  estimator,  while  a  larger  one  may  do  enough  work  to 
keep  several  engineers  busy  in  securing  it. 

It  will  be  assumed  that  the  engineering  department  can  use 
the  services  of  several  men,  two  or  three  assistants  competent  to 
design  and  estimate,  others  for  listing  quantities  and  figuring 
weights,  and  two  or  three  draftsmen  making  general  show  drawings. 

The  chief  engineer  will  give  his  principal  attention  to  outlining 
the  designs  and  selecting  economical  ones.  He  must  examine  de- 
signs made  by  his  assistants  and  check  the  weights  and  costs  by 
rules  and  formulae,  to  see  that  estimates  contain  no  great  mis- 
takes. Time  will  not  generally  permit  checking  estimates  in  detail, 
but  they  should  be  examined  carefully  enough  to  avoid  serious 
errors.  Care  must  be  taken  in  checking,  to  see  that  all  items  are 
included  and  the  large  figures  correct.  There  are  unfortunate 
cases  on  record  where  one-half  of  a  symmetrical  building  was  esti- 
mated, but  the  result  was  not  multiplied  by  two,  or  some  large 
item  like  the  sheathing  or  purlins  was  omitted,  and  the  submitted 
price  was  disastrously  low.  Mistakes  of  this  kind  can  be  easily 
discovered,  and  there  is  no  excuse  for  their  occurrence  if  careful 
assistants  are  selected. 

The  draftsmen  in  the  engineering  department  must  make  neat 
and  attractive  drawings,  even  though  they  have  little  knowledge  of 
construction  detail.  They  must  do  good  lettering  and  printing, 
for  the  drawings  are  the  final  result  of  the  engineer's  work,  and 
the  success  or  failure  in  securing  a  contract  may  depend  on  the 
care  with  which  the  design  is  illustrated.  Each  engineer  must  have 
a  drawing  table,  and  a  desk  for  computations.  Eoll  top  desks  are 
not  suitable,  as  the  tops  interfere  with  spreading  out  the  plans. 
Desks  should  have  tiers  of  drawers  at  the  sides,  and  there  should 
be  other  drawer  cases  for  finished  sheets.  The  engineering  depart- 
ment should  contain  an  abundant  supply  of  literature  on  structural 
engineering,  together  with  bound  series  of  engineering  and  trade 
journals,  and  data  of  every  available  kind  relating  to  designs, 
weights  and  costs.  All  engineering  index  volumes  should  be  at 
hand  in  order  that  subjects  may  be  investigated  and  similar  designs 
examined  in  the  various  technical  reports  and  journals. 


THE  ENGINEERING  DEPARTMENT  493 

The  estimates  and  drawings  must  be  numbered  and  recorded  in 
a  card  index  so  they  can  be  quickly  found.  Estimates  can  be  placed 
in  letter  files,  either  consecutively  or  under  subjects,  putting  those 
for  buildings  of  the  same  kind  together.  In  the  latter  classifica- 
tion, all  foundry  building  estimates  would  be  in  one  file,  machine 
shops  in  another,  store  houses  in  another,  etc.  The  index  cards 
should  be  ruled  with  places  for  various  data,  so  a  large  number  of 
estimates  can  be  glanced  over  quickly  on  the  cards,  without  the 
necessity  of  examining  the  actual  papers. 

OFFICE  METHODS. 

There  is  much  time  and  energy  wasted  in  useless  refinement 
in  the  design  of  ordinary  steel  structures.  Mathematics  is  thought 
by  many  to  be  the  height  of  engineering,  while  it  is  only  an  assist- 
ant to  judgment.  Arbitrary  loadings  are  assumed,  which  in  many 
cases  are  not  realized  within  50  per  cent  or  more,  and  from  these 
assumptions,  calculations  are  carried  out  to  decimals.  The  fol- 
lowing extract  in  this  connection  is  taken  from  the  preface  of 
Trautwine's  Engineers'  Handbook:  "Comparatively  few  engineers 
are  good  mathematicians,  and  in  the  writer's  opinion  it  is  fortunate 
that  such  is  the  case,  for  nature  rarely  combines  high  mathematical 
talent  with  that  practical  tact  and  observation  of  outward  things 
so  essential  to  a  successful  engineer.  There  have  been,  it  is  true, 
brilliant  exceptions,  but  they  are  very  rare.  But  few  even  of  those 
who  have  been  tolerable  mathematicians  when  young  can,  as  they 
advance  in  years,  and  become  engaged  in  business,  spare  the  time 
necessary  for  retaining  such  accomplishments.  Let  the  savants 
work  out  the  results,  and  give  them  to  engineers  in  intelligible 
language.  We  can  afford  to  take  their  word  for  it,  because  such 
things  are  their  specialty.  The  judgment  of  an  experienced  de- 
signer is  often  preferable  to  the  conclusions  of  a  mathematician, 
inexperienced  in  practical  work. 

Stresses  for  ordinary  trusses  may  be  more  quickly  figured  by 
using  the  coefficients  given  in  several  mill  handbooks.  If  these 
do  not  suit  the  form  of  truss,  new  ones  may  easily  be  determined, 
and  all  such  coefficients  should  be  preserved  for  future  use. 

Where  there  are  several  figures  to  be  multiplied  or  divided  by 
the  same  number,  the  use  of  a  slide  rule  or  calculating  machine 
will  save  much  time.  In  other  cases,  figuring  can  be  done  as  easily 
and  quickly  in  the  ordinary  way.  It  is  also  a  saving  of  time  with 
less  liability  to  error  to  perform  all  similar  calculations  on  various 


404  MILL  BUILDINGS 

truss  members  consecutively.  For  example:  first  find  all  the  shears; 
second,  all  the  moments;  third,  all  the  inclined  web  stresses; 
fourth,  all  the  chord  stresses ;  fifth,  all  the  required  tension  areas ; 
sixth,  all  the  required  compression  areas,  etc.,  without  waiting  to 
finish  the  consideration  of  any  one  piece. 

The  estimator  will  have  curves  at  hand  giving  the  weight  of 
trusses  for  a  variety  of  loadings.  To  find  the  weight  of  a  truss, 
intermediate  between  those  for  which  curves  are  available,  it  will 
be  close  enough  for  approximate  estimates  to  interpolate.  Care 
must  be  taken,  however,  to  see  that  the  loads  are  of  the  same  gen- 
eral class.  The  weights  of  steel  in  a  building  for  heavy  cranes 
cannot  be  compared  with  a  similar  one  without  cranes,  nor  a  roof 
in  northern  latitudes  with  one  of  the  same  size  in  the  south. 

When  bids  are  asked  on  a  design  furnished  by  the  owner,  it 
may  be  an  advantage  to  also  submit  a  price  on  an  alternate  one. 
Some  shops  can  fabricate  riveted  work  cheaper  than  they  can 
make  pin-connected  trusses,  and  if  a  price  is  asked  for  a  pin- 
connected  truss,  it  will  doubtless  interest  the  buyer  to  receive  a 
lower  price  on  a  riveted  one. 

In  order  to  have  a  systematic  way  of  recording  all  the  principal 
data  in  connection  with  any  building,  the  following  blank  heading 
will  be  found  convenient  for  estimate  sheets.  The  blank  spaces  for 
size  of  span,  loads,  etc.,  should  all  be  filled,  and  any  other  informa- 
tion not  provided  for  in  the  heading  should  be  written  on  the  first 
page,  together  with  any  governing  extract  from  the  specifications 
which  seriously  affect  the  design.  These  must  appear  on  the  first 
page,  so  a  review  of  the  estimate  can  be  quickly  made : 


PEELIMINAEY  STUDY  SHEET. 


1910  Estimate  No 

Name Sheet of 

Size Area Height No.  Stories 

Distance  between  Trusses Pitch Covering 

No.  Pieces span  clear effective extreme 

Purlins Eaf  ters Monitor 

Compression 

Specification Tension Material 

Live  Load  per  sq.  f t 

Dead  load  per  sq.  f  t 

Designed  by 

Estimated  by 

Drawing  by 

I  |  |  |  |  !  |  |  |  |  |  |  |  I  I  I'  i  !  !  I  I  I  I  I  I  I  I  !  I  I  M 
I  I  I  I  I  !  I  I  I  I  I  I  I  I  I  I  I  I  I  I  I  I  I  I  I  I  I  I  I  I  I  I 
I  I  !  I  I  I  I  I  I  I  1  I  I  I  I  i  !  I  I  !  I  I  I  I  I  I  I  I  I  I  I  I 


THE  ENGINEERING  DEPARTMENT  495 

The  sheets  may  be  ordinary  cap  size,  8  by  13  inches,  and  the 
paper  should  be  a  thin,  strong  linen,  suitable  for  blueprinting, 
cross  ruled  as  shown  in  J  inch  squares.  On  this  paper  the  design 
is  studied  out  on  a  small  scale;  large  sheets  or  scales  are  not 
suitable  for  studies  of  this  kind,  for  attention  is  not  so  easily  con- 
centrated when  sketches  are  spread  over  a  greater  area.  Office 
tables  and  reference  sheets  generally,  to  be  of  the  greatest  use, 
should  be  made  small.  A  reference  sheet,  6  X  8  or  8  X  10  inches, 
that  can  be  easily  handled,  will  be  used  where  a  larger  one  would 
not. 

After  the  general  design  has  been  studied  on  a  small  scale  line 
diagram,  a  cross  section  should  be  made  to  \  or  J  inch  scale,  to 
show  general  details.  These  and  all  stress  sheets  should  be  care- 
fully made  with  india  ink.  All  the  principal  operations  connected 
with  the  calculations  should  be  preserved  for  reference,  but  multi- 
plication may  be  done  on  scrap  paper.  All  principal  dimensions 
must  be  written  in  ink. 

DESIGN. 

In  these  notes  on  office  methods,  questions  of  design  need  be 
considered  onty  briefly,  for  the  subject  is  more  fully  treated  in 
other  chapters.  The  fact  that  prices  submitted  on  the  bidder's  own 
plans  frequently  vary  from  25  to  50  per  cent  above  the  lowest, 
clearly  shows  that  skill  and  care  are  needed ;  and  yet  it  is  generally 
recognized  among  the  building  trades,  that  estimators  of  structural 
iron  work  are  as  a  class  the  most  careful  and  accurate  of  all. 

The  experienced  designer  will  use  standard  parts  wherever  pos- 
sible to  reduce  to  a  minimum  the  amount  of  stress  sheet  work. 
Trusses,  columns,  purlins,  etc.,  for  all  ordinary  purposes  can  be 
computed  and  tabulated  and  will  not  require  refiguring,  and  if 
special  trusses  are  needed,  they  can  be  computed  from  standard 
truss  coefficients. 

STEEL  CAGE  COLUMN  SPACING. 

As  the  weight  of  steel  in  this  class  of  buildings  is  principally 
in  the  floors,  it  follows  that  the  greater  the  number  of  column 
tiers,  within  reasonable  limits,  the  less  will  be  the  weight  of  steel. 
Roughly  speaking,  about  three-fourths  of  all  the  steel  is  in  the 
floors  and  the  remaining  one-fourth  in  the  columns.  Hotels  and 
office  buildings  can  have  columns  fairly  close  together,  for  they 
can  be  placed  in  the  partitions  where  they  cause  no  obstruction. 
On  the  contrary,  stores  or  public  halls  will  permit  only  the  fewest 


406  MILL  BUILDING 

possible  number,  or  none  in  view.  Halls  or  office  buildings  may 
have  stores  in  the  lower  story,  and  then  the  columns  in  the  upper 
stories  must  be  carried  on  heavy  girders  at  the  second  floor.  Office 
buildings  have  also  been  designed  with  few  tiers  of  columns,  so 
partitions  may  be  changed  or  removed  to  suit  the  tenants,  leaving 
an  unobstructed  floor  area.  Warehouses  for  the  storage  of  ordi- 
nary goods  can  usually  have  fairly  close  spacing  of  12  to  16  feet. 
Before  the  position  of  the  columns  can  be  fixed,  there  will,  there- 
fore, be  many  considerations.  It  is  sometimes  economical  to  canti- 
lever the  principal  cross  beams  and  splice  these  beams  at  the  points 
of  contraflexure.  A  twelve-story  apartment  house,  with  small 
rooms,  designed  by  the  writer,  had  columns  spaced  10  feet  apart 
inside  the  partitions.  This  produced  a  very  light  frame,  the 
weight  of  which,  including  floors,  columns  and  complete  frame  for 
the  outside  walls,  was  only  14  pounds  per  square  foot  of  floor  area. 
Another  similar  building,  eleven  stories  high,  in  which  the  col- 
umns were  spaced  25  feet  apart,  weighed  28  pounds  per  square 
foot  of  floor  area.  The  latter  was  an  office  building,  and  was  pro- 
portioned for  heavier  loads  than  the  hotel,  but  the  principal  reason 
for  the  greater  weight  of  steel  was  the  wider  columns  spacing; 
both  had  complete  steel  frames  for  the  outside  walls. 

The  practice  of  designing  columns  in  the  lower  stories  to  carry 
only  a  portion  of  the  sum  of  all  maximum  floor  loads  above  is  rea- 
sonable and  is  allowed  by  the  building  laws  of  some  cities,  though 
not  by  all.  According  to  the  percentages  allowed  by  the  New 
York  building  law,  the  saving  in  the  column  amounts  to  about  10 
per  cent.  This  will  be  from  2  to  3  per  cent  of  the  entire  weight 
of  steel. 

BEAM    SPACING. 

The  distance  between  floor  joist  will  depend  largely  on  the  kind 
of  fireproofing  used.  Most  of  the  concrete  systems  permit  beam 
spacings  from  10  to  15  feet,  but  for  terra  cotta  block  it  should  not 
exceed  about  5  to  8  feet.  Many  architects  use  these  latter  distances 
to  make  the  framing  suitable  for  any  system.  It  requires  less  steel 
to  use  wide  spacing  with  deeper  beams.  The  thickness  of  floor 
may,  however,  be  limited,  and  it  then  becomes  necessary  to  use  a 
shallower  beam  and  smaller  spacing. 

As  the  fireproof  companies  do  not  advertise  their  prices,  it  will 
be  wise  for  the  architect  or  engineer  to  make  several  different 
arrangements  of  beams  for  a  typical  floor,  and  secure  prices  on  the 
fireproofing  for  these  designs.  He  can  then  combine  the  costs  of 


THE  ENGINEERING  DEPARTMENT 


407 


steel  and  fireproofing,  and  select  the  cheapest  arrangement.  He 
should  at  the  same  time  receive  prices  for  fireproofing  one  tier 
of  inside  columns,  to  assist  him  in  choosing  the  best  column 
arrangement. 

Wall  girders  spaced  two  or  three  stories  apart  are  frequently 
as  satisfactory  and  have  less  weight  of  steel  than  when  provided  at 
every  story.  Another  common  practice  is  to  proportion  outside 
columns  to  carry  the  floor  loads  only,  making  the  wall  of  sufficient 
thickness  to  be  self-supporting.  It  is  necessary  to  provide  a  chan- 
nel against  the  wall  to  carry  the  floor,  whether  the  walls  have 
columns  or  not,  though  some  prefer  to  use  a  continuous  flat  plate 
built  into  the  brickwork  and  projecting  about  2  inches  inside  to 
support  the  floor,  while  others  use  a  brick  corbel  instead. 

Whether  to  build  the  outside  walls  of  solid  brick,  or  to  use  a 
steel  frame  with  a  thin  brick  wall  merely  as  a  curtain,  will  depend 
on  the  following  conditions:  First,  which  method  in  itself,  apart 
from  any  consideration  of  available  floor  space,  is  the  cheaper ;  and 


Fig.   630. 

second,  if  the  steel  frame  and  curtain  wall  be  more  expensive, 
whether  or  not  the  increased  floor  space  secured  by  thinner  walls 
will  compensate  for  the  extra  cost  of  construction.  This  second 
consideration  will  occur  only  when  the  lot  area  is  limited  and  land 
values  high.  If  additional  land  can  be  secured  at  a  reasonable 
price,  the  question  of  increasing  floor  space  by  decreasing  the  wall 
thickness  would  not  be  considered. 

Nearly  all  large  business  blocks  and  public  buildings  contain 
more  or  less  iron  and  steel  for  beams,  columns,  wall  plates,  anchors, 


408 


MILL  BUILDINGS 


etc.  It  is  frequently  the  custom  to  make  the  principal  floor  beams 
of  steel,  using  wood  for  other  beams  and  joist.  In  such  cases  the 
parts  must  be  proportioned  to  carry  safely  their  maximum  loads, 
and,  in  large  cities,  to  conform  with  the  building  laws. 

SHOW  DEALINGS. 

After  the  general  design  has  been  carefully  studied,  a  small 
scale  drawing  should  be  prepared,  that  the  buyer  who  may  not  be 
familiar  with  building  details  may  see  the  general  style  of  con- 
struction. Care  should  be  taken,  in  making  general  drawings  and 
show  plans  (Figs.  630,  631  and  632),  to  have  them  neat  and 
attractive,  for  even  though  a  design  contain  much  merit,  if  it  be 


Fig.  631. 

accompanied  with  a  carelessly  made  picture,  it  may  be  passed  by 
and  a  more  attractive  plan  accepted  instead. 

After  the  design  has  been  made,  it  should  be  reviewed  to  see 
where  improvements  are  possible.  Additions  or  reductions  should 
be  made,  extra  bracing  added  where  necessary,  or  the  weight  re- 
duced where  judgment  will  permit.  The  capacity  of  the  original 
design  will  probably  be  kept  up  to  the  buyer's  specifications,  and 
deductions  computed,  which  can  be  made  if  the  capacity  of  certain 


THE  ENGINEEBING  DEPARTMENT 


409 


parts  are  decreased.  For  example,  an  owner  may  think  that  he 
requires  a  building  to  carry  a  50-ton  crane,  but  when  the  cost  is 
considered,  is  willing  to  use  a  crane  of  30  or  40  tons  instead.  All 
suggestions  like  this  will  interest  a  prospective  buyer,  and  will 
increase  the  chances  of  securing  the  work.  If  the  estimate  is  made 
on  a  design  submitted  by  the  bijyer,  alternate  ones  would  doubtless 
be  attractive. 


y 

\ 

><J 

/ 

y 

y 

/ 

x 

>^ 

X 

X 

X 

X 

X 

y 

X  * 

X 

^ 

M. 

I 

—  t. 

/v 

X 

X 

X 

x 

X 

/ 

y 

y 

/ 

y 

x 

Fig.  632. 

Every  estimate  should  be  analyzed  as  soon  as  possible  after  it 
is  completed,  preferably  by  the  one  who  made  it,  and  the  results 
preserved  as  a  basis  for  other  estimates  of  a  similar  kind.  These 
analyses  should  be  kept  on  cards  or  thin  linen  paper  in  loose-leaf 
books,  and  classified  under  different  headings.  Thin  paper  is  pre- 
ferred, as  it  can  be  printed.  By  the  use  of  these  summaries, 
approximate  estimates  for  new  work  can  be  prepared  in  a  very 
short  time. 


CHAPTER  XL. 

ESTIMATING  QUANTITIES. 
APPROXIMATE  ESTIMATES. 

Quantities  may  be  estimated,  either  approximately  by  empirical 
rules  and  formula,  or  exactly,  by  writing  down  the  actual  amounts. 
In  many  cases,  the  approximate  method  is  sufficient,  and  at  all 
times  it  forms  a  valuable  check  or  guide  on  the  final  results.  An 
experienced  estimator  will  have  weight  tables  for  all  kinds  of  steel 
structures,  on  a  square  foot  basis,  so  that  approximate  estimates 
on  new  work  can  be  made  quickly.  In  preparing  approximate  esti- 
mates for  a  proposed  new  building,  care  must  be  taken  to  compare 
with  estimates  for  structures  of  the  same  kind  and  for  similar 
use.  An  approximate  estimate  for  a  building  with  heavy  traveling 
cranes  cannot  be  made  by  comparison  with  a  similar  building  with- 
out cranes,  nor  a  single-story  building  with  a  multi-story  one,  or 
short  spans  with  long  ones.  The  comparison  should  be  with  struc- 
tures as  nearly  like  the  desired  one  as  possible.  A  few  rules  for 
approximate  estimating,  from  the  author's  private  records,  will  be 
given. 

The  weight  of  roof  trusses  for  various  spans,  pitches  and  load- 
ings is  given  by  the  original  charts  in  Part  II,  and  the  weight  of 
trusses  and  plate  girders  for  spans  of  any  length,  and  loads  up 
to  4,000  pounds  per  lineal  foot,  is  given  by  Figs.  119  and  120. 
These  charts  cover  all  kinds  of  loadings  in  ordinary  construction. 

A  formula  for  the  weight  of  roof  trusses  to  sustain  a  total  load 
of  40  pounds  per  square  foot  is  as  follows : 

12      L 

W  —  _  +  _ 

D       20 

where  W,  is  the  weight  of  steel  in  pounds  per  square  foot  or  area  covered; 
L,  the  length  of  span  inside  walls  in  feet ; 
D,  the  distance  in  feet  between  centers  of  trusses. 

The  weight  of  steel  framing  in  mill  buildings,  including  trusses, 
columns,  purlins,  bracing,  etc.,  is  approximately  as  follows : 

Framing  for  roofs  covered  with  corrugated  iron  weighs  from 
4  to  6  pounds  per  square  foot  of  exposed  surface,  while  the  framing 

410 


ESTIMATING  QUANTITIES  41 1 

for  heavier  roofs,  covered  with  slate  or  plank,  will  weigh  from  6 
to  9  pounds  per  square  foot.  These  weights  are  for  roofs  and  side 
walls  only,  and  do  not  include  crane  supports,  floors  or  any  other 
parts,  excepting  the  plain  enclosure.  The  weight  of  steel  framing 
in  walls,  including  columns,  girths,  purlins  and  bracing,  will  sel- 
dom exceed  4  to  6  pounds  per  superficial  foot. 

The  additional  weight  of  steel  required  to  support  traveling 
cranes  in  a  building  will  vary  from  3  to  6  pounds  per  square  foot 
of  the  entire  floor  area,  depending  principally  on  the  capacity  of 
the  cranes  and  the  column  spacing.  This  weight  may  be  more 
closely  approximated  by  allowing  100  pounds  of  steel  per  lineal 
foot  of  building,  for  every  5  tons'  capacity  of  cranes.  These 
weights  are  in  addition  to  the  regular  steel  framing  in  the  roof 
and  walls. 

If  the  weight  of  steel  be  given  in  pounds  per  square  foot  of 
ground  floor,  or  area  covered,  instead  of  per  square  foot  of  exposed 
exterior  surface,  the  weight  will  then  be  approximately  as  follows : 

LT)s.  per  sq.  ft.  of  ground. 

Simple  roofs  without  cranes,  corrugated  iron  covering 6  to  10 

Light  shops  with  cranes 8  to  14 

Heavy  shops  with  cranes,  slate  or  plank  covering 12  to  20 

The  steel  framing  in  roofs  similar  to  Fig.  429  in  spans  from  80 
to  200  feet  weighs  from  8  to  12  pounds  per  square  foot  of  exposed 
surface,  or  from  9  to  16  pounds  per  square  foot  of  ground  covered, 
including  steel  purlins,  which  weigh  from  2  to  4  pounds  per  square 
foot  of  roof. 

None  of  the  above  weights  include  the  steel  in  floors,  which 
may  vary  from  8  to  25  pounds  per  square  foot,  depending  on  the 
arrangement  of  beams,  the  floor  capacity  and  the  distance  between 
columns. 

Multi-story  office  and  warehouse  buildings,  not  over  eleven 
stories  high,  designed  according  to  modern  building  laws,  with 
columns  15  feet  apart,  for  various  imposed  loads,  have  steel  frames 
weighing  as  follows : 

TABLE  LXIV.* 

Lbs.  per                                      Lbs.  per 
sq.  ft.                                               sq.  ft. 
Buildings  for  imposed  loads  of.    .  60       with        outside  frames 14 


Buildings  for  imposed  loads  of. 
Buildings  for  imposed  loads  of. 
Buildings  for  imposed  loads  of. 
Buildings  for  imposed  loads  of. 
Buildings  for  imposed  loads  of. 


60  without  outside  frames 9 

100  with        outside  frames 23 

100  without  outside  frames 15 

250-350  with        outside  frames 28 

250-350  without  outside  frames  . .    .  .  18 


H.  G.  Tyrrell,  Architects'  and  Builders'  Magazine,  Jan.,  1903. 


412  MILL  BUILDINGS 

From  the  above,  an  approximate  estimate  of  the  weight  of  steel 
in  any  proposed  new  multi-story  building  may  very  quickly  be 
made.  The. total  weight  of  floors  increases  in  direct  proportion  to 
the  number  of  stories,  while  the  weight  of  columns  increases  more 
rapidly. 

The  weight  of  cast-iron  column  bases  given  in  Table  XXIV, 
Chapter  XIV,  is  useful  when  estimating  steel  in  tall  buildings.* 

The  steel  framing  in  coal  and  ore  pockets  with  plank  lining 
weighs  from  150  to  200  pounds  for  each  ton  of  coal  or  ore  in  the 
bins,  or  3  to  4  pounds  per  cubic  foot  of  contents.  When  pockets 
have  i-inch  steel  plate  lining,  the  weight  of  steel  is  then  from  200 
to  250  pounds  for  every  ton  of  coal  or  ore. 

The  weight  in  pounds  of  iron  stairs  with  two  steel  stringers  and 
cast  treads  and  risers  (not  including  railings),  per  vertical  foot 
of  building,  is  70+  width  in  feet  X  50.  Cast  risers  ^  inch  thick 
weigh  8  pounds,  and  treads  f  inch  thick,  18  pounds  per  lineal  foot. 

Spiral  iron  stairs  with  treads  33  inches  wide,  weigh  120  pounds 
per  vertical  foot,  and  fire  escapes,  including  stairs  and  platforms, 
have  an  average  weight  of  from  70  to  100  pounds  per  vertical 
foot. 

Iron  lattice  railing  weighs  from  15  to  50  pounds  per  lineal 
foot,  and  pipe  railing  usually  from  8  to  18  pounds  per  foot, 

EXACT   ESTIMATING. 

Exact  estimates  should  be  made  when  time  will  permit  or  when 
their  importance  will  warrant,  and  are  usually  necessary  when 
tendering  on  contract  work.  It  is  desirable  for  the  bidder  to  visit 
the  site  and  personally  examine  the  condition  of  the  soil  and  sur- 
roundings, but  there  is  seldom  time  for  such  excursions,  and  grade 
and  ground  lines  on  the  plans  must  be  followed  instead. 

The  various  kinds  of  work  should  be  listed  in  their  natural 
order,  beginning  with  excavations  and  foundations,  continuing 
with  masonry,  steel  framing,  roofing,  etc.,  and  ending  with  minor 
items  such  as  painting,  plumbing  and  electric  lighting. 

A  convenient  ruling  for  paper  on  which  to  figure  quantities  is 
given  below,  the  various  kinds  of  material  being  kept  in  separate 
columns. 


H.  G.  Tyrrell,  Architects'  and  Builders'  Magazine,  Jan.  1903. 


ESTIMATING  QUANTITIES 
ESTIMATE  SHEET. 


413 


Name. 


Location. 
Owner.  . . 


1910. 

Estimate    No 

Sheet..          ..of   . 


No.  of 
Pieces. 

Material 

Weight 
Per  ft. 

Beam  work  may  be  divided  according  to  the  following  classifi- 
cation : 


Beams  punched  in  either  web  or  flange. 
Beams  punched  in  both  web  and  flange. 
Beams  coped  or  framed. 

Double  beams  bolted  together  with  separators. 
Plain  beams  not  punched. 


Beam  fittings,  such  as  separators,  bolts  and  connections,  should 
be  kept  separate,  as  a  special  price  is  charged  for  them.  An  extra 
price  may  be  made  for  beams  18  inches  deep  and  over,  and  these 
should  also  be  separated  from  beams  15  inches  deep  and  smaller. 
Where  only  a  rough  estimate  is  required,  it  will  be  convenient  to 
use  one  column  for  each  different  weight,  and  write  down  the  total 
length  when  figuring  off  the  beams.  For  example,  in  place  of 
writing  2  I-beams,  15  inch  @  42  pounds  per  foot,  X  24  feet  long, 
simply  write  the  total  number  of  lineal  feet  (48)  in  the  42  pound 
column. 

It  is  easier  to  figure  off  only  one  piece,  or  if  the  section  is  sym- 
metrical like  a  double  pitch  roof  truss,  then  figure  off  only  half. 
The  total  number  of  pieces  may  be  given  in  the  weight  summary. 
The  weight  of  truss  details  is  usually  found  by  adding  20  to  35 
per  cent  to  the  weight  of  main  members,  but  the  total  weights,  in- 
cluding details  for  all  ordinary  trusses,  can  be  taken  directly  from 


414  MILL  BUILDINGS 

the  charts.  The  weight  of  rivets  varies  from  3  to  6  per  cent  of  the 
whole,  and  allowance  may  be  made  for  column  caps  and  bases  by 
adding  2  or  3  feet  to  the  length  of  the  column. 


LISTING   MISCELLANEOUS   ITEMS. 

It  is  frequently  necessary  to  include  in  the  steel  contract  such 
material  as  lumber,  paving,  doors,  windows,  and  occasionally  the 
entire  mason  and  carpenter  work.  It  is  the  custom  to  place  the 
contract  for  the  whole  building  with  the  contractor  whose  share  is 
the  largest.  Therefore,  with  steel  frame  buildings,  where  steel  is 
the  largest  single  item,  all  the  other  kinds  of  material  must  be  in- 
cluded. If  there  is  much  other  work,  it  is  better  to  secure  sub- 
bids,  but  if  little,  this  may  not  be  necessary.  Windows  should  be 
listed  with  outside  dimensions,  stating  if  sash  are  hung  or  fixed, 
with  the  size  and  number  of  lights  in  each.  Windows  in  the  side  of 
monitors  are  operated  from  the  floor  either  by  cords  or  shafts  and 
gears,  and  the  number  to  be  opened  must  be  stated.  Gutters  and 
conductors  are  listed  by  the  number  of  lineal  feet  and  size;  roof- 
ing  by  the  number  of  square  feet;  paving  by  the  square  yard; 
railing  by  the  number  of  lineal  feet  and  the  weight  per  foot;  lum- 
ber by  the  number  of  feet  board  measure,  keeping  different  kinds 
separate. 

Wall  anchors  fastening  floor  joist  to  masonry  are  spaced  about 
10  feet  apart,  and  plate  anchors  5  feet  apart.  The  number  and 
size  of  other  mason's  and  carpenter's  anchors  are  too  uncertain  to 
classify,  and  where  these  items  are  large,  should  be  figured  from 
a  schedule,  but  where  their  weight  is  small  compared  with  other 
work,  the  experienced  estimator  will  include  a  lump  sum  to  cover 
them. 

If  the  estimate  is  onxa  design  prepared  by  others,  an  approxi- 
mate estimate  should  be  made  on  another,  for  the  purpose  of 
checking  the  economy  of  the  original  one,  for  one  designer  can 
often  save  on  the  work  of  another. 


CHECK  LISTS. 

In  order  to  know  that  all  items  have  been  included,  it  is  con- 
venient to  have  a  check  list  at  hand  for  reference,  which  may  be  re- 
viewed before  making  the  summary.  If  any  items  have  been 
omitted,  they  may  then  be  included. 


ESTIMATING  QUANTITIES 


415 


TABLE  LXV. 
CHECK  LIST— BUILDINGS.* 


Bed  Plates 
Brackets 
Crane  Rods 
Columns 

End 

Crane 

Clear  story 

Lean  to 

Main 

Finish  Angles 
Floor 

Beams 

Joist 

Plates 
Girders 

Crane 

Plate  or  Lattice 
Knee  Braces 
Purlins 

End 

Gable 

Roof 

Side 
Eods 

Longitudinal  Ties 

Lateral 

Sag  Ties 

Sways 

Ties 

Separators 
Struts 

Bottom  Chord 

Crane 

Eave 

Rafter 
Sway 


Trusses 

Lower  Chords 

Rafters 

Struts 

Suspenders 

Ties 
Ventilators 

Braces 

Circular 

Frames 

Trusses 
Wall  Plates 
Anchor  Bolts 
Bolts 
Cotters 
Clips 

Corrugated  Iron 
Crane  Track 
Doors 

Door  Frames 
Flashing 

Gutters  and  Downspouts 
Louvres 
Name  Plates 
Pins 
Paint 
Rivets 
Railing 

Ridge  Capping 
Stairs 

Sheet  Metal  Work 
Sheeting  Rivets 
Wood  Work 
Windows 


FINAL  CLASSIFICATION. 


In  all  operations,  uniform  methods  should  be  adopted  as  far 
as  possible.  Therefore,  in  making  the  final  classification,  it  is 
convenient  to  have  a  blank  form  such  as  given  below,  one  of  which 
may  be  filled  out  for  each  estimate.  The  cost  of  stock  is  first 
considered  by  giving  the  weight  of  each  kind,  figured  at  the  cur- 
rent price  per  pound.  The  cost  of  drawings  and  templets  is  then 
found  by  giving  the  number  of  sheets  which  are  figured  at  a  certain 
price  per  sheet.  The  cost  of  labor  is  next  computed,  by  giving  the 
number  of  pounds  of  trusses,  girders,  columns,  castings,  beams, 
machine  work,  etc.,  each  being  figured  at  its  own  pound  price. 
Miscellaneous  items  bought  from  other  makers  are  figured  by 
themselves,  and  paint  is  estimated  by  giving  the  number  of  gal- 
lons. Then  follows  the  cost  of  transportation,  including  freight, 


416 


MILL  BUILDINGS 


GENERAL  SUMMARY. 


Name             .              .      .              Estimate  No 

Location                                             ...      -  -        -        Shppf.  .  ...          .-  _nf    

Materials. 
Stock  — 
Plates    sheared       .... 

Quantities. 

Unit  Price. 

Total  Cost. 

Plates,   rolled   edge 

Bars    common 

Bars,    refined    

Angles     

Beams,    24    in  

Beams,  20   in  

Beams,  15  in.  and  under      .  . 

Z  bars    

T  bars   

Eye  bars   

Cast  iron   

Rivets 

Bolts 

Pins  and  rollers 

Steel  ioist 

Office  and  Shop  Labor  — 
Drawings 

Templets    

Trusses 

Girders 

Columns 

Bracing 

Beams    coped  or  framed 

Beams    punched 

Beams   plain 

Steel  "joists    punched  at  mill 

Machine  work 

Cast  shoes    etc 

Fence 

Fence  posts                         .  . 

Paint    1st  coat 

Miscellaneous  Items  — 
Lumber 

Spikes             .      .  . 

Doors 

Windows,  etc    .        

Erection  — 
Steel  ...                

Steel  joists      

Paint    ^d  coat 

Lumber 

Lumber    "joists 

Lumber  stagino° 

Bolts    staging 

Fence    . 

teaming,  railroad  fares  for  erection  crew,  and  finally  the  cost  of 
erection  labor.  By  separating  all  the  items  in  this  way,  a  close 
estimate  is  secured.  It  is  of  much  greater  importance  to  have  all 
items  included,  than  to  have  a  fine  classification,  though  the  latter 


ESTIMATING  QUANTITIES  417 

is  desirable.  One  or  two  important  items  omitted  from  an  estimate 
might  easily  cause  a  greater  difference  in  the  total  than  would 
result  by  figuring  the  entire  riveted  steel  work  at  some  even  unit 
price  such  as  $70.00  per  ton,,  and  while  varying  shop  costs  are 
given,  the  most  important  part  of  an  estimate  is  to  see  that  all 
items  are  included  and  a  small  amount  added  for  contingencies. 
If  there  is  any  doubt  about  certain  parts,  they  may  be  figured 
separate  from  the  rest. 

Finally,,  it  should  be  definitely  stated  on  the  summary  sheet, 
just  what  items  are  included  and  what  are  not.  These  should  all 
be  specified  so  the  buyer  may  know  exactly  what  is  and  is  not 
covered  by  the  price. 


CHAPTER  XLI. 

ESTIMATING  COSTS. 

APPEOXIMATE    COST    ESTIMATES. 

Approximate  cost  estimates  are  sufficient  for  many  purposes, 
and  can  be  made  in  less  time  than  exact  ones.  They  are  found 
from  the  cost  units  per  square  foot  of  floor  area  and  per  cubic 
foot  of  contents,  for  buildings  of  various  kinds,  given  in  Chapters 
VI  and  VII. 

Approximate  costs  are  also  found  from  the  weights  in  the  pre- 
ceding chapter,  multiplied  by  their  respective  unit  prices.  Both 
methods  can  be  used,  one  being  a  check  upon  the  other. 

CLOSE    COST    ESTIMATES. 

To  arrive  at  close  estimates  all  the  various  items  that  make  up 
the  final  cost  must  be  considered  separately,  including  designs, 
drawings,  materials,  shopwork,  freight,  hauling,  erection,  paint- 
ing, etc.  It  simplifies  office  work  to  use  uniform  methods  wherever 
possible,  and  the  quantities  and  cost  units  should  therefore  be  writ- 
ten for  each  estimate  on  a  blank  form  similar  to  that  on  page  413. 
The  paper  is  conveniently  ruled  in  columns,  and  there  is  space  left 
for  additional  items  such  as  doors,  windows,  etc. 

The  cost  of  the  engineering  department,  including  designs  and 
contracting  expenses,  may  vary  from  one  half  of  one  per  cent  to 
one  per  cent  of  the  estimates,  and  this  amount  should  be  added 
to  each  estimate. 

Drawings  should  be  figured  at  $15  per  sheet,  or  according  to 
the  tonnage  costs  for  drawings  given  in  Chapter  XLVI. 

COST  OF  MATERIALS. 

The  cost  of  materials  varies  according  to  the  condition  of  the 
market,  and  these  costs  are  frequently  reported  in  the  engineering 
papers  and  trade  journals.  If  the  prices  quoted  are  those  at  the 
mill  where  they  are  produced,  freight  charges  from  the  mill  to  the 
shop  must  be  included,  in  addition  to  the  cost  of  freighting  the 
finished  products  from  the  shops  where  fabrication  is  done,  to  the 
building  site. 

418 


ESTIMATING  COSTS  419 

TABLE  LXVI. 

PRICE  OF  STRUCTURAL  STEEL,  AT  THE  MILLS,  PITTSBURG,  PA.       (DECEMBER, 

1910.) 

Beams  3  to  15  in $1.45  per  Ib. 

Beams,  over  15  in 1.55  per  Ib. 

H  shapes  over  8  in 1.65  per  Ib. 

Angles  3  to  6  in.,  over  14  in.  thick 1.50  per  Ib. 

Angles  over   6    in 1.55  per  Ib. 

Angles  3X3  and  upward,  less  than  *4  in-  thick 1.70  per  Ib. 

Tees  3  in.  and  over .  .  .  . 1.60  per  Ib. 

Zees  3  in.  and  over 1.50  per  Ib. 

Angles,  channels,  tees,  under  3  in 1.45  per  Ib. 

Deck  beams  and  bulb  angles ]  .75  per  Ib. 

The  cost  of  material  on  the  cost  sheet  should  be  the  mill  price, 
with  freight  charges  added  from  mill  to  shops  where  the  struc- 
tural work  is  fabricated,  or  the  cost  of  material  delivered  at  the 
shops.  When  material  is  required  in  too  short  a  time  to  permit 
waiting  for  rolling  it  in  exact  lengths,  it  is  then  customary  when 
cut  from  long  stock  lengths  to  charge  from  .2  to  .3  of  a  cent  more 
per  pound. 

Prices  on  brick,  cement,  lumber,  etc.,  are  given  in  Chapter 
XLII,  but  they  should  be  revised  to  suit  the  time  and  place,  as 
market  prices  vary  in  different  localities.  In  the  South  and  West 
where  it  is  plentiful,  good  timber  costs  less  than  in  the  North  and 
East,  where  it  must  be  hauled.  The  cost  of  other  materials  Is 
given  in  greater  detail  under  their  proper  headings. 

COST    OF   LABOE   AND   SHOP   WOEK. 

The  cost  of  shop  work  depends  largely  on  the  cost  of  labor, 
which  varies  with  location.  The  wages  paid  to  mechanics  in  the 
building  trades  in  various  parts  of  the  United  States  in  1910  are 
given  in  Table  LXVII. 


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4:22  MILL  BUILDINGS 

The  cost  of  making  wood  templets  averages  $12  for  each  sheet 
of  drawings. 

TABLE  LXVIII. 

COST  OF  SHOP  WORK,  NOT  INCLUDING  DRAWINGS  OR  OFFICE  EXPENSES. 

Cents. 

Built  columns,  500  Ibs.  weight  or  less 80  per  Ib. 

Built  columns,  weighing  more  than  500  Ibs.  each 70  per  Ib. 

Trusses,  weighing  less  than  1,000  Ibs.  each 1.00  per  Ib. 

Trusses,  weighing  from  1,000  to  2,000  Ibs.  each    90  per  Ib. 

Trusses,  weighing  from  2,000  to  3,000  Ibs.  each    -.80  per  Ib. 

Trusses,  weighing  more  than  3,000  Ibs.  each 70  per  Ib. 

Plate  girders,  heavy    60  per  Ib. 

Plate  girders,  light    50  per  Ib. 

Kiveted  bracing,  struts,  etc 70  per  Ib. 

Punched   purlins , 20  per  Ib. 

Columns  made  of  H  shapes,  rolled  by  the  Bethlehem  Steel 
Company,  have  a  less  shop  cost  than  those  made  from  separate 
shapes  riveted  together,  but  a  higher  pound  price  is  charged  for 
the  material,  so  the  saving  by  their  use  is  small. 

Beams  and  channels  can  be  purchased  from  the  rolling  mills, 
punched  and  framed,  according  to  submitted  drawings,  and  shipped 
directly  to  the  building  site  and,  wherever  possible,  it  is  economy 
to  buy  in  this  way  as  the  additional  cost  of  handling  and  freight 
charges  are  saved.  The  following  charges  must,  therefore,  be 
added  to  the  base  prices  given  above,  when  beams  and  channels 
are  punched  or  framed  at  the  mills. 


TABLE  LXIX. 

Cents. 

(1)  For  cutting  to  length  with  less  variation  than  plus  or  minus 

%   in 15 

(2)  Plain  punching  one  size  hole  in  web  only 15 

(3)  Plain  punching  one  size  hole  in  one  or  both  flanges 15 

(4)  Plain  punching  one  size  hole  in  either  web  and  one  flange  or 

web  and  both  flanges 25 

(5)  Plain  punching  each  additional  size  hole  in  either  web  or  flanges, 

web  and  one  flange  or  web  and  both  flanges 15 

(6)  Plain  punching  one  size  hole  in  flange  and  another  size  hole  in 

web  of  the  same  beam  or  channel 40 

(7)  Punching  and  assembling  into  girders 35 

(8)  Coping,   ordinary  beveling,   including   cutting  to   exact   length, 

with  or  without  punching;  including  the  riveting  or  bolting 

of  standard  connection  angles 35 

(9)  For  painting  or  oiling,  one  coat,  with  ordinary  paint  or  oil 10 

(10)  Cambering,  beams  and  channels  and  other  shapes  for  ships  or 

other  purposes 25 

(11)  Bending,  or  other  unusual  work,  shop  rates. 

(12)  For  fittings,  whether  loose  or  attached,  such  as  angle  connections, 

bolts  and  separators,  tie  rods,  etc 1.55 

Tie  rods  in  all  cases  where  estimated  upon  in  connection  with  beams  or 
channels  are  to  be  classified  as  fittings. 


ESTIMATING  COSTS  433 

It  is  cheaper  to  field  rivet  a  few  connection  angles  to  heavy 
beams  and  order  the  beams  with  punching  only,  rather  than  pay 
the  higher  charge  for  punching  and  riveting.  The  few  connection 
angles  would  then  be  sent  with  other  riveted  material  from  the 
structural  shop. 

The  cost  of  shop  work  varies  considerably,  depending  on  the 
equipment,  and  it  is  needless  to  use  cost  units  with  too  fine  a 
gradation. 

COST  OF  FREIGHT. 

When  the  shop  that  is  manufacturing  the  structural  work  is 
a  long  distance  from  the  source  of  raw  material,  which  comes 
chiefly  from  the  Pittsburg  district,  freight  charges  must  be  paid; 
first,  for  shipping  raw  material  to  the  shop,  and  second,  when 
shipping  the  manufactured  products  from  the  shop  to  the  building 
site.  As  raw  material  can  be  loaded  on  cars  more  compactly  than 
riveted  sections,  it  is  economical  to  have  the  fabrication  done  at  a 
plant  near  the  proposed  building,  so  freight  charges  will  be  chiefly 
on  raw  material. 

TABLE  LXX. 

FREIGHT  RATE  PER  100  POUNDS,  ON  STRUCTURAL  STEEL  FROM  PITTSBURG. 
(DECEMBER,  1910.)     IN  CARLOAD  LOTS. 

Pittsburg  to  New  York 16  cents  per  100  Ibs. 

Pittsburg  to  Philadelphia,   Pa 15  cents  per  100  Ibs. 

Pittsburg  to  Boston    18  cents  per  100  Ibs. 

Pittsburg  to  Buffalo 11  cents  per  100  Ibs. 

Pittsburg  to  Cleveland 10  cents  per  100  Ibs. 

Pittsburg  to  Cincinnati    15  cents  per  100  Ibs. 

Pittsburg  to  Chicago    18  cents  per  100  Ibs. 

Pittsburg  to  Indianapolis    17  cents  per  100  Ibs. 

Pittsburg  to  St.  Paul 32  cents  per  100  Ibs. 

Pittsburg  to  St.  Louis  22  cents  per  100  Ibs. 

Pittsburg  to  New  Orleans 30  cents  per  100  Ibs. 

Pittsburg  to  Kansas  City   42%  cents  per  100  Ibs. 

Pittsburg  to  Birmingham,  Ala 45  cents  per  100  Ibs. 

Pittsburg  to  Coast  cities 80  cents  per  100  Ibs, 

Pittsburg  to  Denver  92%  cents  per  100  Ibs. 

The  ability  to  make  low  prices  on  steel  structural  work  de- 
pends largely,  if  not  entirely,  on  the  freight  charges.  A  shop  east 
of  Pittsburg  cannot  compete  for  western  work  against  western 
shops,  for  raw  material  must  then  be  shipped  east  from  Pittsburg 
and  the  finished  product  reshipped  west  again.  The  tender  of  the 
eastern  shop  would  exceed  western  prices  by  the  freight  charge 
from  Pittsburg  to  the  eastern  shop  and  back  again.  Shops  can, 
therefore,  compete  for  work  only  when  they  are  located  in  the  vicin- 
ity of  the  proposed  new  building,  or  when  a  shipment,  going  from 


424  MILL  BUILDINGS 

the  Pittsburg  district  to  the  building  site,  could  pass  their  shop 
without  much  extra  cost. 

There  is  greater  variation  in  erection  costs  than  in  any  other 
part  of  the  work,  for  differences  of  20  to  30  per  cent  will  some- 
times occur,  depending  upon  how  well  the  drawings  have  been 
made  and  manufacturing  executed. 

The  cost  of  erecting  beams  and  columns  in  buildings  with 
brick  walls  is  from  $6  to  $10  per  ton,  and  if  the  mason  does  the 
hoisting,  the  remaining  cost  of  erection  would  then  be  from  $4 
to  $8  per  ton.  Erecting  steel  work  in  buildings  with  several  stories, 
including  hoisting  and  painting,  costs  from  $8  to  $10  per  ton  when 
the  trusses  are  riveted  and  all  other  joints  bolted,  while  heavy 
mill  buildings  will  cost  from  $11  to  $15  per  ton.  The  erection  of 
small  buildings  with  all  joints  bolted,  the  parts  of  which  can  be 
hoisted  with  gin  poles,  will  not  exceed  about  $6  per  ton. 

There  are  usually  about  ten  field  rivets  for  every  ton  of  struct- 
ural steel,  and  these,  at  10  cents  each,  make  the  cost  of  field  rivet- 
ing about  $1.00  per  ton.  Field  rivets  driven  under  favorable  cir- 
cumstances with  the  structural  work  on  skids  or  on  the  ground, 
will  not  cost  more  than  5  to  8  cents  apiece,  while  those  driven 
with  the  parts  erected  in  position  and  the  workmen  standing  on 
scaffolding  or  staging,  may  cost  from  15  to  20  cents  each.  Bolts 
are  usually  as  good  as  rivets  for  field  connection  and  are  more 
economical. 

A  pier  shed  in  Xew  York  City,  56  feet  wide  and  545  feet  long, 
was  erected  in  nine  working  days  by  fifty  men,  working  eight  hours 
per  day.  The  building  was  covered  with  corrugated  iron,  con- 
tained 350  tons  of  steel,  and  trusses  were  spaced  20  feet  apart. 

Another  similar  pier  shed  in  Xew  York  was  erected  by  a  crew 
of  ten  men  who  averaged  four  trusses  per  day  including  all  bracing. 

COST  OF  ESTIMATING  AND  TIME  REQUIRED. 

The  time  occupied  in  making  an  approximate  estimate  of  any 
ordinary  structure  need  not  exceed  a  few  minutes,  as  weights  can 
be  taken  from  curves  or  figured  from  formulas. 

In  taking  off  quantities  and  figuring  the  weight  of  steel  cage 
construction,  a  man  can  estimate  about  300  tons  per  day.  There- 
fore, if  a  proposed  new  building  contains  1,500  tons  of  steel,  it  can 
be  taken  off  and  estimated  by  one  man  in  five  days,  or  several  men 
in  proportionately  less  time. 

The  estimating  of  mill  buildings  and  light  construction  requires 


ESTIMATING  COSTS  425 

more  time.  An  engineer,  who  is  continuously  employed  on  build- 
ing work,  will  probably  estimate  from  10,000  to  15,000  tons  of 
steel  per  year,  and  secure  from  10  to  20%  of  this  in  contracts.  A 
good  estimator  would  then  obtain  contracts  for  1,000  to  3,000  tons 
of  steel  per  year.  A  man  regularly  occupied  in  this  work,  would 
probably  average  four  to  five  estimates  per  week,  and  the  cost  of 
these,  including  show  drawings,  would  be  from  $10  to  $15  each. 

TENDERS. 

After  adding  all  the  items  that  affect  the  final  cost,  including 
2  to  3  per  cent  for  contingencies,  the  contractor  will  add  whatever 
profit  he  considers  the  work  worth,  and  submit  his  tender.  He 
should  state  very  clearly  what  is  or  is  not  included  in  his  price, 
so  there  will  be  no  misunderstanding.  If  the  estimate  is  on 
plans,  which  have  been  submitted  to  him,  it  will  probably  be  a 
benefit  for  the  contractor  to  make  one  or  more  alternate  prices  or 
reductions  for  proposed  changes  from  the  plans,  or  he  may  sub- 
mit a  different  plan  and  a  price  thereon.  In  any  case,  the  pro- 
posal must  state  that  the  price  is  based  on  plans  and  specifications, 
so  there  can  be  no  misunderstanding. 

Tenders  should  be  written  in  the  following  forms.  The  first 
is  for  a  steel  mill  building  erected  complete,  while  the  second  is  a 
proposal  on  a  building  for  export,  and  the  price  given  is  for  ma- 
terial only,  not  including  ocean  freight  or  erection. 

PROPOSAL  FOR  A  STEEL  MILL  BUILDING  ERECTED  IN  THE 
UNITED  STATES. 

Chicago,  111.,  January  1,  1910. 
The  Wright  Air  Ship  Company, 

Chicago  111. 

Gentlemen: — We  propose  to  supply  all  labor  and  furnish,  deliver  and 
erect  at  the  site,  all  material  necessary  to  complete  a  building  for  the 
Wright  Air  Ship  Company,  according  to  plans  and  specifications",  for  the 

sum  of dollars.     This  proposal  includes  all  structural  steel  work, 

corrugated  iron,  gutters,  conductors,  flashing,   louvres,   doors  and  windows, 
painted  two  coats,  bub  does  not  include  either  ground  floor  or  foundations. 
(Signed)      The  Mill  Construction  Company, 

John  Jones,  Secretary. 

PROPOSAL  FOR  MATERIAL  IN  MILL  BUILDING  FOR  EXPORT. 

Chicago,  111.,  January  1,  1910. 
The  Oriental  Shipping  Company, 

Hong  Kong,   China. 

Gentlemen: — We  propose  to  furnish  and  deliver  F.  O.  B.  cars  on  the 
wharf  at  New  York  city,  all  steel  structural  work,  corrugated  iron,  gutters, 
down  spouts,  louvres,  flashing,  wire  netting,  doors,  windows,  and  glass, 
together  with  all  necessary  nails,  rivets,  bolts,  etc.,  for  erection,  in  a  build- 
ing for  the  Oriental  Shipping  Company,  Hong  Kong,  China,  for  the  sum  of 


426  MILL  BUILDINGS 

dollars,  according  to  the  accompanying  drawing.  This  quota- 
tion does  not  include  ocean  freight,  erection  or  the  cost  of  ground  floor, 
foundations,  partitions,  or  any  material  except  that  stated.  The  shipment 

will  contain    pieces,  having  a  shipping  weight   of    

tons  and  occupy cubic  feet  in  the  vessel. 

(Signed)     The  American  Structural  Company, 

William  Brown,  President. 

PEEPAEATION    OF   ESTIMATE    FOE    DEAFTING   EOOM. 

When  a  contract  is  secured,  the  design  should  be  carefully  re- 
viewed ,  all  dimensions  verified,  directions  made  distinct  and  clear, 
and  the  design  plainly  illustrated.  After  several  days,  places  may 
be  found  where  improvements  can  be  made  or  the  work  cheapened. 
The  picture  drawing  should  be  made  to  correspond  with  the  re- 
vised strain  sheets. 

All  notes  or  instructions  should  be  written  and  accompany  the 
estimate,  as  some  requirements  can  be  more  easily  described  than 
illustrated.  Instructions  about  shipping,  when  material  will  be 
needed,  and  which  parts  first,  whom  to  see  or  correspond  with  to 
secure  further  information,  color  of  paint  and  number  of  coats, 
etc.,  should  be  all  noted  in  writing.  The  contract  may  not  include 
all  items  in  the  estimate  and  it  should  be  clearly  stated  what  it 
covers.  When  all  data  and  papers  in  connection  with  the  work 
have  been  collected,  they  should  be  blue  printed  for  the  drafting 
office,  and  the  originals  kept  on  file  for  record.  Some  shops  give 
to  the  drafting  office  prints  of  only  such  sheets  as  are  needed,  re- 
serving weights  of  steel  and  cost  pages. 


CHAPTER  XLIII. 

APPROXIMATE   ESTIMATING  PRICES. 

Materials — Delivered. 

Cement,  Portland,  Pacific  Coast,  per  bbl $     2.20  to  $     2.50 

Cement,  Portland,  East,  per  bbl 1.35  to  1.75 

Cement,  Eosendale,  per  bbl 80  to  1.00 

Cement,  Non-staining,  per  bbl 3.00  to  3.50 

Lime,  per  bu 20  to  .25 

Sand,  per  cu.  yd 1.00  to  1.50 

Gravel,  per  cu.  yd 1.00  to  1.25 

Crushed  limestone,  per  cu.  yd 75  to  1.25 

Crushed  granite,  per  cu.  yd 3.00  to  3.50 

Stone  sill,       8X12  ins.    per  lineal  ft 1.25 


Stone  sill,  5X12  ins. 

Stone  sill,  4X   8  ins. 

Stone  sill,  5X   8  ins. 

Stone  sill,  4X10  ins. 


per  lineal  ft .80 

per  lineal  ft .45 

per  lineal  ft .60 

per  lineal  ft .60 

Stone  steps,  7X14  ins.,'  per  lineal  ft .90 

Brick,  common,  per  M 6.00  to       10.00 

Brick,  face,  per  M 25.00  to       30.00 

Brick,  molded,  per  M 40.00  to       50.00 

Brick,  enameled,  per  M 70.00  to       80.00 

Masonry — In  place. 

Excavating,  general,   per  cu.   yd 25  to  .50 

Excavating,  trench,   per   cu.   yd 50  to         1.00 

Excavating,  under  water,  per  cu.  yd , 3.00  to         4.00 

Filling,  per  cu.  yd 25  to  .50 

Eubble — Masonry,  Eosendale  Cement,  per  cu.  yd 4.50  to         5.50 

Bubble — Masonry,  Portland  Cement,  per  cu.  yd 5.50  to         6.50 

Bedford  limestone,  per  cu.  ft 1.60 

Carthage  limestone,  per  cu.   ft 2.30 

Kasota  or  Mankota  stone,  per  cu.  ft 2.80 

Granite,  per  cu.  ft 3.50 

Bedford  Ashlar,  4  to  8  ins.  thick,  per  sq.  ft 1.00 

Blue  stone  pier  caps,  per  cu.  ft 2.00 

Ground  floors,  1  in.  cement  on  6  in.  concrete,  per  sq.  yd.  1.40 
Ground  floors,  %  in.  cement  on  41/£   in.  concrete,  per 

sq.  yd 1.25 

Ground  floors,  asphalt  on  6  in.  concrete,  per  sq.  yd.  ...  1.40  to         3.25 

Ground  floors,  asphalt  block,  per  sq.  yd 2.00  to         2.50 

Ground  floors,  wood  block,  per  sq.  yd 1.50  to         2.25 

Ground  floors,  brick  paving,  per  sq.  yd 2.50 

Concrete  sidewalk,  per  sq.  yd 1.80  to         2.40 

Concrete  sidewalk,  surface  finish  only,  per  sq.  yd .60  to           .90 

Upper  floors,  fireproof,  including  form,  per  sq.  ft 35  to  .45 

Piling. 

Wood  piling,  in  place,  driven  and  cut,  per  liu.  ft 25  to  .35 

Concrete   piling,  in  place,  per  lin,  ft 1.25 

Sheet  piling,  in  place,  per  M 40.00 

Concrete — 

Concrete   in   place,   large   mass,,   natural   cement,    per 

cu.  yd  $  4.00  to  $     5.00 

Concrete  in  place,  Portland  cement,  per  cu.  yd 5.00  to         7.00 

427 


428 


MILL  BUILDINGS 


Concrete,  in  wall  with  forms,  per  cu.  yd 6.00  to  8.00 

Reinforced  concrete,  roof  slabs,  15  ft.  span,  sq.  ft .25  to  .30 

Reinforced  concrete,  floor  slabs,  8-10  ft.  (cone.,  steel  and 

forms) ,  per  sq.  f t .30  .40 

Cement  floor  surface  finish,  per  sq.  ft .07 

Reinforced  concrete,  including  steel,  per  cu.  yd 10.00  to  12.00 

Reinforced  concrete,  including  steel  and  forms,  per  cu. 

yd. 16.00  to  20.00 

Reinforcing  bars,  plain,  per  ton 30.00 

Reinforcing  bars,  patent,  per  ton 50.00 

Forms  for  reinforced  concrete,  per  sq.  ft .05  to  .08 

Reinforced  girder  and  columns  (cone.,  steel  and  forms), 

per  lin.  ft 1.00 

Reinforced  columns,  wound,  per  lin.  ft 1.70 

Wood  forms  for  reinforced  beams  and  columns,  per 

lin.  ft .50 

2-in.  concrete  roof  slab  on  trussit,  per  sq.  ft .15  to  .18 

3-in.  concrete  roof  slab  on  trussit,  per,  sq.  ft .20  to  .22 

No.  10  expanded  metal,  4  in.  mesh,  per  sq.  f  t .035 

3-in.  concrete  roof  slab  and  expanded  metal,  per  sq.  ft.  .  .15 
3-in.  concrete  partition  slabs  and  expanded  metal,  with 

%  channel,  per  sq.  ft .17 

Brickwork. 

Common,  in  lime  mortar,  per  M 18.00 

Common,  in  Rosendale  cement,  per  M 19.00 

Common,  in  Portland  cement,  per  M 20.00 

Face  brick,  per  M 45.00 

Moulded  brick,  per  M 70.00 

Enamel  brick,  per  M 100.00 

Carpentry  and  Mill  Work. 

Windows  and  doors,  complete  with  glass  and  finish,  per 

sq.   f  t .50 

Windows  and  doors,  frames  only,  in  place,  per  sq.  ft .  .  .20 

Sash,  1%-in.  thick,  not  glazed,  per  sq.  ft .07 

Sash,  2% -in.  thick,  not  glazed,  per  sq.  ft .14 

Sash,  glazed  and  painted,  in  place,  per  sq.  ft 15  to  .25 

Double  floors  on  wood  joist,  per  sq.  ft 12  to  .16 

Spruce  lumber,  in  place,  per  M 25.00 

H.  P.  joists,  purlins,  etc.,  in  place,  per  M 30.00 

H.  P.  matched  flooring,  in  place,  per  M 35.00 

Maple  flooring,  No.  1  factory,  I%xl3/16  ins.,  per  M.  .  .  70.00  to       80.00 

Lumber  in  cofferdams,  per  M 40.00 

Board  fence,  per  lin.  ft 50  to         1.00 

Stairs,  3  ft.  wide,  good  finish,  per  step 2.50  to         3.00 

Stairs,  3  ft.  wide,  rear,  per  step 1.50  to         2.00 

Structural  Steel. 

Steel  truss  and  column  framing,  in  place,  per  ]b .04 

Steel  beams,  in  place,  per  Ib .03 

Plain  Castings,  per  Ib .02 

Ornamental  Iron. 

Mason  treads,  per  sq.  f  t 2.00 

Elevator  fronts,  per  sq.  ft 1.00  to         2.00 

Iron  stairs,  3  ft.  wide,  5c.  per  pound,  per  step 8.00  to         9.00 

Fire  escape,  lOc.  per  pound,  per  story 100.00 

Metal  clothes  lockers,  18X20X72  ins.,  in  place,  eacli.  .  8.00 

Pipe  railing,  1  line,  per  lin.  ft .50 

Pipe  railing,  3  line,  per  lin.  ft 1.00 

Railing,  plain  lattice,  per  lin.  ft 2.00  to         3.00 

Railing,  fancy  lattice,  per  lin.  ft 4.00  to         5.00 

Cast  iron  cols.,  plain,  per  Ib .015 

Cast  iron  cols.,  ornamental,  per  Ib .03 


APPROXIMATE  ESTIMATING  PRICES  429 

Roofing. 

Slate  on  board  (boards  not  included),  per  sq 7.00  to       13.00 

Tin  on  board  (boards  not  included),  per  sq 10.00  to       12.00 

Gravel  on  board  (boards  not  included),  per  sq 5.00  to         6.00 

Composition  on  board  (boards  not  included),  per  sq.  .  .  2.00  to         5.00 

Wood  shingles  on  board  (boards  not  included),  per  sq.  3.00  to         5.00 

Corrugated  iron  on  purlins,  per  sq 7.00  to         9.00 

Metal  tile,  tin,  per  sq 8.00  to       10.00 

Metal  tile,  lead  coated,  per  sq 10.00  to       14.00 

Sheet  copper,  per  sq 35.00  to       40.00 

Ornamental  clay  tiles,  per  sq 40.00  to       60.00 

Spanish  tile,  per  sq 22.00 

Ludowici,  per  sq 16.00 

Sheet  Metal  Work. 

Metal  windows,  without  glass,  hung,  per  sq  ft .55 

Metal  windows,  without  glass,  trunnioned,  per  sq.  ft.  .  .40 
Metal  windows,  glazed,  with  polished  wire  glass,  per 

sq.  ft 1.10 

Metal  windows,  glazed,  with  ribbed  or  maize  glass,  per 

sq.  f t .80 

Ribbed  or  maize  glass,  any  size,  in  place,  per  sq.  ft ....  .25 

Double  strength  clear  glass,  per  sq.  ft .07  to           .10 

Richardson  metal  doors,  per  sq.  ft 1.30 

Rolling  steel  shutters,  per  sq.  ft .50 

Corrugated  iron  doors  and  shutters,  per  sq.  f  t .35 

Metal  louvres,  fixed,  per  sq  f  t .40 

Metal  louvres,  hinged,  per  sq.  ft .60 

Round  ventilators,  each 5.00  to     100.00 

Corrugated  iron,  No.  26  galvanized,  in  place,  per  sq .  . .  6.50 

Corrugated  iron,  No.  26,  black,  in  place,  per  sq 4.50 

Corrugated  iron,  No.  22,  galvanized,  in  place,  per  sq.  . .  9.00 

Corrugated  iron,  No.  22,  black,  in  place,  per  sq 7.00 

Corrugated  iron,  No.  20,  black,  in  place,  per  sq 9.50 

Corrugated  iron.  No.  18,  black,  in  place,  per  sq 11.50 

Galvanized  cornice,  in  place,  per  sq.  f  t .12 

Copper  cornice,  16  ounce,  per  sq.  f  t .35 

Lath  and  Plaster. 

Wood  lath,  in  place,  per  sq.  yd .08  to           .12 

Metal  lath,  in  place,  per  sq.  yd .18  to           .20 

Plaster,  3  coats,  interior,  per  sq.  yd .20  to           .21 

Plaster,  3  coats,  on  wood  lath,  interior,  per  sq.  yd .28  to           .33 

Plaster,  2  coats,  on  metal  lath,  interior,  per  sq.  yd ....  .40 

Plaster,  3  coats,  on  metal  lath,  interior,  per  sq.  yd .50 

Plaster,  on  Sacket  board,  per  sq.  yd. 30  to  .36 

Exterior  plaster,  2  coats,  on  brick  wall,  without  lath, 

per  sq.  yd 50  to  .60 

Rough  cast  on  2  coats  of  plaster  and  metal  lath  for  cov- 
ering frame  building,  per  sq.  yd 80  to  .90 

Painting. 

Prepared  paint,  per  gal .60  to         1.50 

Painting  structural  steel,  per  coat,  per  ton 1.00 

Painting  miscellaneous  iron  work,  per  ton 1.50 

Surface  painting,  1  coat,  per  sq.  yd .10  to           .12 

Surface  painting,  2  coats,  per  sq.  yd 18  to  .20 

Surface  painting,  3  coats,  per  sq.  yd 25  to  .28 

Plumbing. 

Water  closets,  in  place,  with  pipes  and  attachment,  each  70.00 

Slop  sinks,  in  place,  with  pipes  and  attachment,  each.  .  60.00 

Lavatories,  in  place,  with  pipes 50.00 

Marble  toilet  room  partitions,  per  sq.  ft 1.25 

Marble  toilet  bases,  countersunk,  per  sq.  ft 1.85 


CHAPTER  XLIII. 

V 

THE  DRAFTING  OFFICE. 

The  office  is  the  principal  workshop.  Xo  part  of  industrial 
plants  shows  greater  progress  than  the  office  and  drafting  rooms. 
Twenty  years  ago  many  offices  were  only  a  few  dingy  and  ill-lighted 
rooms  partitioned  off  from  the  shop,  the  air  loaded  with  gas  and 
fumes,  the  floors  uneven  and  the  ceilings  festooned  with  cobwebs. 

The  modern  office  should  contain  everything  necessary  for  the 


Fig.  633. 

convenience  and  comfort  of  its  occupants,  in  order  that  they  may 
give  their  best  service.  These  features  should  exist  in  an  equal  or 
greater  degree  than  in  the  shops,  because  office  men  or  brain  work- 
ers with  less  physical  exercise  are  usually  of  a  more  nervous  tem- 
perament. As  the  office  produces  no  dust  or  dirt,  there  is  no 
reason  why  its  interior  arrangements  cannot  be  made  both  con- 

430 


THE  DRAFTING  OFFICE  431 

venient  and  attractive.     It  must  be  light,  well  ventilated  and  have 
arrangements  for  heating  in  winter  and  cooling  in  summer. 

LOCATION. 

In  large  works  it  is  customary  to  locate  the  drafting  office  on 
the  upper  floors  of  the  executive  building,  because  this  office  is 
constantly  in  communication  with  the  management.  The  whole 
office  building  should  be  centrally  located  and  convenient  to  the 
shops,  and  the  sketches  in  Chapter  I  show  it  as  the  group  center, 
with  shops  around  it.  The  drafting  office  and  the  templet  shop 
are  so  often  in  consultation  that  many  plants  have  these  two  de- 
partments in  the  same  building,  the  former  occupying  the  second 
floor  of  the  templet  building.  The  arrangement  is  not  entirely 
satisfactory,  however,  for  the  templet  shop  is  noisy,  often  dusty, 
and  contains  dry  combustible  lumber,  which  exposes  the  office  con- 
tents to  serious  fire  risk.  The  more  recent  practice  is  to  house  all 
records  and  drawings  in  a  fireproof  building,  using  one  or  two 
lower  floors  for  executive  offices  and  upper  floors  for  drafting  rooms. 
These  several  story  buildings  should  have  elevators  and  stairs,  the 
elevator  taking  passengers  up  and  the  stairs  being  used  in  coming 
down. 

There  is  a  noticeable  tendency  towards  moving  large  drafting 
offices  from  the  city  to  the  suburbs,  but  this  is  more  applicable  to 
city  offices  which  have  no  shop  connection  than  for  shop  offices.  It 
has  the  advantage  of  lessening  the  rent,  while  employees  have  better 
light  and  air,  and  because  of  rural  surroundings,  can  do  better  work. 
At  the  suburban  office,  draftsmen  can  spend  the  noon  hour  out  in 
the  sunshine,  by  the  water  or  among  the  trees,  rather  than  on  the 
hot  and  dusty  pavements  in  the  foul  city  atmosphere.  The  draft- 
ing offices  of  several  architectural  firms  have  been  moved  each  sum- 
mer to  the  seashore,  in  the  belief  that  the  workers  will  not  only 
be  benefited,  but  will  also  do  more  and  better  work. 


THE  BUILDING. 

A  fireproof  building  is  the  only  kind  suitable  for  housing  valu- 
able drawings.  It  should  be  fireproof  in  order  that  drawings  in 
use  can  safely  be  left  at  the  draftsmen's  tables  instead  of  being 
placed  every  night  in  a  vault.  The  drawings  and  records  are  so 
valuable,  that  a  fire  loss  can  never  be  covered.  In  addition  to  the 
building  being  fireproof,  it  should  contain  one  or  more  record 


432 


MILL  BUILDINGS 


THE  DRAFTING  OFFICE  433 

rooms  built  like  vaults,  with  the  least  amount  of  combustible  ma- 
terial, for  storing  drawings  no  longer  in  regular  use. 

As  far  as  constructive  features  are  concerned,  an  office  building 
is  similar  to  those  used  for  light  manufacturing.  There  is  no 
reason  why  work  in  an  office  cannot  be  done  as  well  or  better  on 
several  floors  as  on  a  single  floor.  On  the  other  hand,  the  building 
with  several  floors  has  better  air  and  light,  and  costs  less  for  the 
required  floor  area.  The  subject  of  relative  economy  of  buildings 
with  one  or  more  stories  has  been  discussed  in  Chapter  IV.  It  has 
been  shown  that  the  greatest  economy  for  light  floor  loads  results 
from  using  buildings  of  not  less  than  three  or  four  stories,  for 
above  the  first  story  there  is  no  further  expense  for  roof  or  ground, 
the  only  extra  expense  being  for  the  floor  and  enclosing  walls. 

WELFAEE  FEATURES. 

Nearly  all  large  factory  offices  are  making  provision  in  some 
way  for  the  comforts  and  needs  of  the  workers.  In  structural  offices 
it  is  customary  to  find  a  room  devoted  to  library  purposes,  where 
technical  and  trade  journals  pertaining  to  the  business  are  on  file. 
This  feature,  while  very  agreeable  to  the  employees,  is  not  charitable, 
for  the  owners  are  benefited  in  giving  the  workmen  opportunities 
to  learn  from  the  trade  journals  the  latest  and  best  working  meth- 
ods. These  rooms  are  supplied  with  technical  books  pertaining  to 
structural  engineering,  so  all  ma}'  become  proficient.  Arrange- 
ments are  made  for  taking  books  and  magazines  out  over  night,  by 
leaving  a  card  with  some  one  who  has  charge  of  the  room. 

A  dining  room  is  another  provision,  where  meals  are  served  for 
a  small  sum,  usually  not  much  over  cost  price.  Some  works  have 
their  own  dining  room  on  the  top  floor  of  the  office  building,  but 
this  is  a  mistake,  for  many  men  remain  in  the  building  from  morn- 
ing till  night.  It  is  better  to  have  the  dining  room  in  a  separate 
building  at  a  distance  from  the  office,  so  all  will  get  out  in  the 
open  air  at  the  noon  hour.  The  exercise  in  the  open  air  is  bene- 
ficial and  gives  a  change  of  thought  and  outlook.  Service  buildings 
of  this  kind  are  shown  in  Fig.  2.  A  ball  ground  is  another  com- 
mon provision.  The  game  takes  thought  away  from  work,  and 
gives  the  men  clearer  brains  for  the  afternoon's  duties. 

The  Toledo  office  of  the  American  Bridge  Company,  shown  in 
Figs.  633  and  634,  is  located  on  the  outskirts  of  the  city,  in  a 
district  free  from  smoke  and  dust,  with  a  lawn  around  the  building, 


434 


MILL  BUILDINGS 


THE  DRAFTING  OFFICE  435 

and  two  tennis  courts  in  the  rear.  The  basement  contains  kitchen, 
dining  room,  bicycle  rooms  and  general  toilet. 

The  best  place  for  a  printing  room  is  in  the  upper  story,  or  on 
the  roof,  where  direct  sunlight  is  always  available.  Besides  the 
general  printing  room,  there  should  be  a  dark  room  for  making 
sensitive  paper  and  for  photo  developing.  The  modern  printing 
room  is  equipped  with  both  sunlight  frames  and  electric  printing 
machines.  The  light  from  electric  machines  is  so  much  more  uni- 
form than  the  varying  sunlight,  that  many  offices  prefer  to  use  it 
exclusively.  With  these  machines,  there  is  no  need  for  estimating 
the  degree  of  light,  as  it  is  uniform,  and  the  same  kind  of  paper 
will  always  print  in  the  same  length  of  time.  When  printing  by 
sunlight,  especially  on  cloudy  or  partly  cloudy  days,  the  clouds 
.  must  be  carefully  watched,  so  the  print  will  have  the  right  amount 
of  light. 

Photography  is  an  important  part  of  an  office  equipment,  for 
all  important  buildings  made,  should  be  photographed,  and  some 
shops  are  using  photo  reproduction  for  drawings,  especially  those 
for  field  or  erection  use.  The  cost  of  photo  reproduction  exceeds 
ordinary  blue  printing  by  only  15  to  20  per  cent,  and  the  advantage 
from  the  smaller  drawings  is  great. 

The  type  printing  machine  may  be  kept  either  in  the  printing 
room  or  in  the  general  drawing  office.  It  is  used  for  placing  titles, 
or  any  other  wording  that  is  repeated  on  several  drawings. 

The  printing  room  of  the  Brown-Sharpe  Company  is  shown  in 
Fig.  635.  There  should  be  heating  coils  and  drying  racks  over 
dripping  trays  lined  with  zinc. 

THE  FILE  AND  EECOED  EOOM. 

While  the  entire  office  building  should  be  fireproof,  so  drawings 
can  safely  be  left  on  the  draftsmen's  tables,  there  should  be  storage 
vaults  for  complete  drawings  which  are  used  only  for  occasional 
reference.  These  record  rooms  should  be  as  nearly  fireproof  as 
possible,  with  tile  floors  and  sheet  metal  filing  drawers.  Some  offices 
insist  on  placing  all  drawings  every  night  in  the  safe  or  vault,  caus- 
ing a  daily  loss  of  time  in  waiting  for  them.  In  these  offices  it  is 
common  for  fifty  men  or  more  to  lose  ten  to  fifteen  minutes  twice 
a  day  in  collecting  drawings  for  the  vault,  and  waiting  their  turn 
to  be  served.  Drawings  that  are  in  daily  use  or  in  course  of  mak- 
ing, should  be  kept  at  draftsmen's  tables,  and  the  vault  used  only 
for  those  drawings  which  are  completed.  The  record  room  should 


436 


MILL  BUILDINGS 


be  in  charge  of  one  person  who  is  responsible  for  the  safe  keeping 
of  records.  There  should  be  a  complete  card  index  in  the  drafting 
room  adjoining  the  vault,  so  drawings  can  be  easily  found.  When 
drawings  are  delivered,  a  receipt  card  should  be  left  until  they  are 
returned. 


Fig.  636. 

There  should  also  be  small  drawers  for  filing  photo  plates  and 
films,  each  one  being  placed  inside  an  envelope,  with  a  blue  print 
of  the  plate  pasted  on  the  outside,  in  order  that  the  picture  can 
be  seen  without  removing  the  original. 

A  common  fault  with  record  rooms  is  that  they  are  too  small 
for  handling  and  sorting  drawings.  They  should  be  large  and 
spacious,  and  have  a  counter  or  table  for  holding  tracings  before 


Fig.   637. 


filing.    The  drawers  in  the  record  room  should  be  26  by  38  inches, 
with  hinged  lids  at  the  front  to  hold  the  drawings  down. 


THE  SUPPLY  BOOM. 


The  store  room  for  stationery  and  supplies  should  be  convenient 
to  the  drafting  office,  and  need  contain  only  enough  supplies  for 


TEE  DRAFTING  OFFICE  437 

immediate  use,  being  replenished  occasionally  from  the  general 
store.  A  few  drawers  or  a  locker  press  in  the  drafting  room  may 
be  sufficient. 

INSIDE  AEEANGEMENT. 

The  interior  of  the  office  should  be  so  furnished  and  arranged 
that  accurate  drawings  can  be  made  with  the  least  interruption  and 
the  greatest  ease.  It  should  have  a  solid  floor,  free  from  vibration, 
and  a  wearing  surface  of  pine  or  maple.  The  principal  space  will 
be  used  for  drafting  tables,  placed  around  the  wall,  with  the  left 
end  adjoining  the  windows.  They  should  stand  crosswise  and  not 
facing  the  wall,  for  then  light  is  better,  and  the  work  of  various 
men  is  separated.  Tables  should  be  spaced  not  less  than  four  feet 
apart,  so  the  men  will  have  plenty  of  room  for  free  movement. 
Down  the  center  of  the  room  should  be  a  line  of  drawer  cases  with 
drawers  on  both  sides  for  drawings  that  are  in  use.  The  tops  of 
these  tables  are  convenient  for  sorting  and  spreading  plans.  Draw- 
ers should  have  double  handles  and  a  metal  holder  on  each  for  a 
card  label.  There  are  many  kinds  of  drawing  tables,  most  of  them 


Fig.  638. 


existing  because  of  patent  royalties  which  their  originators  receive. 
Xo  table  is  more  convenient  than  one  3  feet  wide,  ti  feet  long  and 
3  feet  6  inches  high  with  adjustable  hinged  leaf  on  the  right  end, 


438 


MILL  BUILDINGS 


which  can  be  madk  of  pine  in  any  carpenter  shop.  There  should 
be  a  tier  of  three  drawers  6  by  15  inches  at  the  right  end,  and 
three  large  drawers  at  the  center  28  by  40  inches  wide  and  3  inches 
deep.  The  office  should  have  an  assortment  of  inclined  raising 
blocks  of  different  heights,  for  elevating  the  drawing  board  to  a 
convenient  position.  In  addition  to  these,  the  tables  may  have 
extension  legs,  to  be  used  or  removed  to  suit.  Other  kinds  of  tables 
are  shown  in  Figs.  636  to  640.  Figure  641  shows  the  interior  of  an 
office  where  the  table  tops  are  hinged  and  can  be  raised  or  lowered 
as  desired.  These  vertical  drawing  boards  are  not  satisfactory,  for 


Fig.  639. 


Fig.   640. 


articles  will  not  remain  on  them.  The  only  sloping  part  should  be 
the  drawing  board,  and  not  the  table  top,  for  a  level  table  is  needed 
for  books  and  papers.  Adjustable  drawing  tables  soon  become  un- 
steady and  the  absence  of  drawers  is  a  detriment.  Each  table 
should  have  a  revolving  high  stool,  with  circular  foot  rests,  mounted 
on  rubber  tips,  and  a  low  chair  for  occasional  use.  The  regular 
drawing  boards  should  be  not  less  than  30  X  48  inches,  but  there 
should  be  a  few  larger  ones,  36  X  60  inches,  for  occasional  special 
work,  and  some  smaller  ones,  18  X  24,  for  studies.  Drawing  boards 
should  be  1^  inches  thick  or  more,  and  they  may  be  lightened  by 
grooving  out  the  backs,  and  stiffened  by  two  mortised  cross  bars. 
They  must  receive  neither  oil  nor  varnish.  It  is  convenient  to 
have  a  light  gas  pipe  frame  in  front  of  each  table,  from  which  to 
suspend  general  or  reference  drawings,  as  shown  in  Fig.  641.  The 
upper  rail  should  have  sliding  spring  clips  or  fasteners  to  grip  the 


THE  DEAFTING  OFFICE 


439 


drawings.  On  the  wall  adjoining  the  tables  there  should  be  in- 
dividual book  cases  with  locks,  as  shown  in  Fig.  634,  and  near  the 
entrance  a  clothes  room  with  separate  lockers  for  each  occupant. 
These  will  add  greatly  to  the  neatness  of  the  room. 

Yellow  or  other  colored  drawing  paper  is  less  tiresome  to  the 
eyes  than  white,  and  is  therefore  preferred.  Colored  paper  is  sold 
in  rolls,  and  one  or  two  of  these  may  be  mounted  on  rollers  in  the 
drafting  office  and  paper  cut  off  in  lengths  as  needed.  White  paper 
is  sold  in  sheets  and  may  be  kept  in  drawers.  Boll  paper  is  satis- 


Fig.  641. 


factory  for  ordinar}^  structural  drawings,  but  as  it  warps  and  will 
not  lie  flat  on  the  board,  is  unsuitable  for  fine  work.  For  small 
scale  drawings  with  much  detail,  strong  white  sheets  which  will 
stand  erasing  are  preferable.  The  paper  sheets  of  ordinary  struct- 
ural work  are  kept  only  until  the  work  is  erected  or  completed, 
when  they  are  of  no  further  use  and  may  be  destroyed.  Tracings 
only  are  retained. 

It  was  formerly  the  practice  in  some  offices  to  place  wood  par- 
titions about  7  feet  in  height  between  the  tables,  making  separate 
stalls  or  compartments.  This  prevented  attention  being  turned  to 
the  work  of  others  and  made  more  wall  space  on  which  to  hang  up 


440  MILL  BUILDINGS 

drawings;  but  the  partitions  obstruct  light  and  permit  those  to 
shirk  who  are  inclined  to  idleness,  so  preference  is  now  to  have 
the  entire  office  clear  of  partitions  which  prevent  the  men  from 
being  seen  from  every  part  of  the  room.  For  this  reason,  stair,  ele- 
vator shafts  or  vaults  that  are  needed  near  the  center  of  the  drafting 
room  should  be  built  out  from  the  main  building,  leaving  the  main 
room  rectangular  in  shape  and  allowing  each  table  to  be  seen,  as 
shown  in  Fig.  642. 

The  office  superintendent  should  have  a  private  room  either  at 
one  end  or  near  the  middle  of  the  main  floor,  with  continuous  glass 
around  the  sides  above  the  wainscot.  The  glass  allows  him  to 
see  the  entire  office,  and  forms  no  obstruction  to  sight.  It  may  be 
located  at  one  end,  as  shown  in  Fig.  642,  with  a  second  stairway  to 
the  floor  below.  Where  there  is  only  one  stairway,  the  superintend- 
ent's room  is  more  convenient  near  the  center  of  the  drafting  room, 
adjacent  to  the  stairs  and  elevator. 

There  should  be  speaking  tube  and  dumb  waiter  to  the  blue 
print  room  and  a  private  telephone  system  connecting  all  depart- 
ments and  the  shops.  The  order  department  is  in  close  touch  with  the 
drafting  office,  and  an  order  room  may  be  made  at  one  end,  as  shown 
in  Fig.  642.  In  this  department  all  material  is  ordered  that  is  re- 
quired for  the  building,  much  of  it  being  copied  from  the  bills  on 
the  drawings.  A  valuable  addition  to  the  drafting  room  is  a  cata- 
logue case  with  a  classified  card  index,  and  each  catalogue  num- 
bered. The  case  should  be  locked,  and  when  books  are  taken,  a 
memoranda  card  should  be  left  with  the  name  of  the  borrower,  and 
date  taken.  Sweet's  indexed  catalogue  contains  a  summary  of 
many  others,  but  there  is  much  information  in  the  originals  too 
bulky  to  be  contained  in  it. 

The  drafting  office  should  have  a  system  of  loose-leaf  scrap  books 
for  clippings  pertaining  to  the  business.  It  is  customary  for  manu- 
facturing companies  to  receive  duplicate  copies  of  trade  journals, 
and  one  set  may  be  used  for  clippings.  An  hour  or  two  should  be 
set  apart  by  the  engineer  or  chief  draftsman  for  reveiwing  these 
journals,  and  the  work  of  marking,  clipping  and  arranging  in  loose- 
leaf  books  can  be  done  by  a  clerk.  After  the  journals  are  reviewed 
in  the  drafting  office,  they  should  be  passed  on  to  another  depart- 
ment for  further  clippings  valuable  to  them.  There  should  also 
be  loose-leaf  books  with  views  of  recent  plants  or  buildings. 


TEE  DRAFTING  OFFICE 


441 


NATUEAL  LIGHTING. 

Eibbed  glass  in  the  upper  sash  will  better  diffuse  light  through- 
out the  room  than  plain  glass,  but  the  lower  sash  should  have  heavy 
clear  glass  with  adjustable  lower  blinds  raising  from  the  bottom. 
In  upper  stories,  one  or  two  box  skylights  are  desirable  with  ad- 
justable shades,  but  they  must  be  carefully  made  to  prevent  water 
from  driving  in  during  heavy  storms  and  destroying  the  drawings. 


Fig.  642. 


Leakage  at  night  may  do  serious  damage  before  being  discovered. 
Skylights  are  good  only  for  general  lighting,,  as  shadows  are  cast 
by  the  body  on  the  drawing  board.  Light  should  come  from  the 
left,  and  is  best  when  tables  are  arranged  with  their  ends  adjoin- 
ing the  windows.  The  amount  of  light  is  doubled  when  the  in- 


442 


MILL  BUILDINGS 


terior  walls  and  ceiling  is  white  or  a  light  color.  There  should  be 
a  wainscot  of  dark  color  about  5  feet  above  the  floor,  but  the  re- 
mainder of  the  walls  and  ceiling  may  be  colored  light  blue  or  green, 
which  will  not  soil  as  quickly  as  white  and  is  not  so  tiresome  to  the 
eyes.  The  furniture  and  wood  work  should  preferably  be  finished 
in  natural  wood,  oiled  and  varnished.  The  general  effect  will  be 
better  than  when  a  dark  stain  or  paint  is  used. 


Fig.  643. 


AETIFICIAL  LIGHTING. 

The  drafting  room  must  be  well  lighted,  for  effective  work  is 
impossible  without  it.  The  best  kind  of  artificial  lighting  results 
from  a  combination  of  arc  and  incandescent  lamps.  Figure  645, 
taken  at  night,  shows  an  arrangement  of  lamp  shades  throwing  the 
light  to  the  ceiling,  from  which  it  is  reflected  uniformly  to  the 
floor.  In  addition  to  the  ceiling  lights,  there  should  be  individual 
ones  at  the  tables  with  green  shades,  either  suspended  by  cords  or 
held  by  adjustable  arms  or  brackets,  so  light  can  be  concentrated 
at  any  place. 


TEE  DRAFTING  OFFICE  443 

HEATING  AND  VENTILATING. 

If  heating  coils  are  used  beneath  the  windows,  the  degree  of 
heat  should  not  be  so  great  that  air  will  be  excessively  warm  near 
the  radiators  and  chilly  in  the  middle  of  the  room.  Improper  heat- 
ing is  frequently  the  cause  of  colds  and  sickness  and  can  be  avoided. 
When  warm  air  from  a  heating  chamber  is  blown  into  the  office,  it 
may  be  passed  through  a  washing  vapor,  and  only  clean  air  sup- 
plied. This  is  a  great  advantage  when  offices  are  located  in  a  smoky 
district,  adjoining  the  works.  Impure  air  and  smoke  in  the  office  is 
not  only  injurious  to  the  occupants,  but  it  soils  and  damages  the 
drawings  and  other  contents  of  the  building.  The  process  of  wash- 
ing, therefore,  supplies  clean  air  at  all  times,  warmed  in  winter  and 
cooled  in  summer.  If  ventilation  is  insufficient,  it  may  be  improved 
by  a  few  ceiling  fans,  at  small  expense,  as  shown  in  Figs.  644  and 
645. 

LAVATOEIES  AND  PLUMBING. 

Toilet  rooms  should  be  placed  on  each  floor,  with  one  bowl  for 
every  ten  or  twelve  occupants.  Where  less  provision  is  made,  there 
will  be  loss  of  time  at  certain  hours  of  the  day.  There  must  also 
be  washbowls  in  the  toilet  room  and  several  individual  ones  in  the 
drafting  room.  Cooled  and  filtered  drinking  water  may  be  piped 
through  the  building  from  a  center  filter,  or  it  may  be  supplied 
from  separate  cooling  tanks  in  the  various  rooms. 


CHAPTER  XLIV. 

ORGANIZATION    OF   DRAFTING   OFFICE. 

The  drafting  offices  of  many  large  structural  plants  are  an  im- 
portant part  of  their  organization.  In  them  designs  are  originated 
and  details  perfected.  Drafting  office  practice  has  a  double  interest 
to  the  designer  of  mill  buildings,  for  not  only  is  the  engineer  in- 
terested in  the  organization  and  management  of  the  office  in  which 
he  himself  is  engaged,  but  he  is  also  interested  in  making  office 
buildings  for  other  industrial  plants. 


Fig.   644. 

The  engineering  department  of  a  structural  company  engaged  in 
the  design  and  manufacture  of  steel  mill  and  industrial  buildings 
is  generally  divided  into  two  principal  parts,  (1)  the  designing  and 
estimating,  and  (2)  the  drafting  and  detailing  departments.  A 
description  of  the  usual  methods  followed  in  the  designing  and  esti- 
mating department  is  given  in  another  chapter,  and  the  drafting 

444 


ORGANIZATION  OF  DRAFTING  OFFICE  445 

office  practice  only  is  discussed  here.  As  the  drafting  depart- 
ment contains  from  four  to  five  times  as  many  men  as  are  needed 
in  estimating,  there  is  need  for  economy  and  uniform  working 
methods. 

Drawings  are  the  principal  medium  by  which  knowledge  of 
a  design  is  conveyed  from  one  man  or  set  of  men  to  another.  The 
art  of  drawing  has  been  likened  to  a  language,  and  those  who 
understand  it  best  are  best  able  to  express  their  thoughts  by  draw- 
ings and  to  read  and  learn  the  thoughts  so  expressed. 

It  is  assumed  here  that  designs  and  general  plans  are  already 
made,  and  the  drafting  department  is  called  upon  to  elaborate  these 
designs  and  make  working  drawings.  The  purpose  of  details  is  to 
supply  the  workmen  in  the  shop  with  such  information  as  they  will 
need,  and  to  answer  all  their  inquiries.  The  draftsman  should 
remember  that  while  he  may  have  the  data  by  which  to  verify 
dimensions  or  clearances,  the  workmen  in  the  shop  have  no  such 
data  and  must  make  the  pieces  exactly  as  they  are  shown,  without 
perhaps  even  knowing  their  location  in  the  building,  or  to  what 
other  pieces  they  connect.  He  should  therefore  make  a  very  careful 
study  of  two  questions :  ( 1 )  what  information  should  be  given  to 
the  shop,  and  (2)  how  that  information  can  best  be  given. 

The  economic  organization  and  management  of  drafting  offices, 
where  the  office  force  is  engaged  in  designing  and  detailing  steel 
mill  buildings,  is  important,  because  nearly  all  such  buildings  have 
their  particular  needs  and  require  special  plans.  It  is  very  seldom 
that  a  set  of  plans  made  for  one  building  is  suitable  for  reproduc- 
tion. The  great  proportion  of  manufacturing  done  at  structural 
shops  is  special  work,  and  this  requires  the  services  of  a  large  num- 
ber of  skilled  workmen.  Draftsmen  are  well  paid  workmen,  and  the 
expense  of  these  offices  is  high.  There  is,  therefore,  need  for  careful 
organization  to  get  the  best  results  for  the  least  money. 

Making  drawings  for  structural  steel  work  is  important,  because 
of  the  value  of  steel  and  the  time  required  in  procuring  it.  A 
building  contractor  in  making  timber  trusses  does  not  need  elaborate 
details,  showing  the  exact  position  of  holes  for  nails  and  bolts,  for 
these  holes  can  be  bored  after  the  timbers  are  assembled,  and  spikes 
or  nails  driven  where  required.  If  a  mistake  is  made  in  boring 
these  holes,  the  loss  incurred  is  not  great  and  no  long  delay  would 
follow,  for  well  stocked  lumber  yards  are  everywhere  and  new  timber 
could  be  bought  at  a  day's  notice.  In  steel  construction  the  condi- 
tions are  different.  Boring  holes  in  metal  is  not  economical,  and 
the  various  parts  composing  a  truss  are  cut  and  punched  before 


446 


MILL  BUILDINGS 


being  assembled.  With  timber  trusses,  if  a  piece  is  found  too  long, 
it  can  easily  be  shortened  with  a  hand  saw  without  sending  it  back 
to  the  shop  or  to  a  shearing  machine.  With  steel  framing,  it  is 
economical  to  have  all  the  parts  cut  to  their  correct  length  and  shape 
and  all  holes  punched  in  their  exact  position  before  the  parts  are 
assembled.  When  the  various  pieces  for  a  wooden  building  are 
shipped  to  the  site,  if  mistakes  are  discovered,  columns  or  purlins 
found  too  long,  it  will  take  but  a  few  minutes  to  cut  them  off  and 


Fig.  645. 


remedy  the  error,  but  if  similar  mistakes  are  discovered  in  parts  of 
a  steel  building,  the  pieces  would  need  shipping  back  to  the  works, 
causing  several  days'  delay,  or  it  might  be  possible  to  cut  off  the 
surplus  length  with  sledge  hammers  and  cold  chisels ;  in  either  case 
to  remedy  the  error  is  expensive. 

Accuracy  is  therefore  the  chief  essential  in  a  structural  drafting 
room.  It  has  been  conclusively  proven  that  money  spent  in  making 
clear  and  neat  drawings  that  can  be  read  without  difficulty,  and  in 
checking  and  verifying  them,  is  saved  many  times  before  the  work 
is  completed. 

Draftsmen  should  make  a  practice  of  frequently  visiting  the 


OEGANIZATION  OF  DEAF  TING  OFFICE  447 

shops  and  studying  and  examining  their  practices.  They  should  be 
as  familiar  with  these  methods  as  are  the  shop  men  themselves. 
Draftsmen  will  find  it  greatly  to  their  benefit  to  converse  freely  with 
the  workmen  and  particularly  with  the  department  foremen,  who 
are  usually  pleased  to  give  information.  There  is  no  better  way 
for  a  draftsman  to  become  conversant  with  shop  methods. 

Jealousy  and  rivalry  are  often  the  cause  of  scant  courtesy  be- 
tween various  departments.  It  is  better  for  the  proprietors  and 
stockholders,  and  also  for  the  men  themselves,  that  friendly  rela- 
tions be  maintained,  for  there  will  then  be  better  cooperation  with 
correspondingly  better  results.  It  is  the  custom  in  some  organiza- 
tions which  have  numerous  departments  to  have  frequent  evening 
meetings  of  the  department  managers  to  arrange  the  work  for  the 
best  interests  of  all ;  this  brings  the  various  departments  to  work  in 
unison  with  less  misunderstanding  and  fewer  losses. 

Draftsmen  as  a  class  are  accustomed  to  moving  about  freely 
from  one  plant  to  another  in  order  to  broaden  their  knowledge 
and  experience.  The  subdivision  of  labor,  even  in  drafting  offices, 
which  keeps  one  man  or  set  of  men  continuously  at  one  kind  of 
work,  is  largely  responsible  for  this  frequent  moving.  The 
monotony  of  constant  indoor  work  of  the  same  kind  makes  even 
the  expense  and  trouble  of  moving  a  pleasure  for  the  change 
secured.  Changes  are  so  frequent  in  structural  drafting  offices 
and  new  men  so  often  employed  that  large  companies  issue  illus- 
trated pamphlets,  setting  forth  in  detail  their  methods  of  making 
drawings  and  doing  work.  These  pamphlets  in  many  cases  are 
quite  elaborate  and  are  either  printed  in  type  or  bound  in  blue 
print  form.  They  show  the  shop  and  office  practice,  and  draftsmen 
must  familiarize  themselves  with  these  methods  and  incorporate 
them  in  their  work.  Many  shops  that  formerly  left  minor  details 
to  the  templet  makers  are  now  having  these  details  figured  on  the 
drawings,  and  this  makes  extra  work  in  the  drafting  room. 

Any  set  of  rules  drawn  for  the  guidance  of  draftsmen  will  need 
modification  to  adapt  it  to  a  particular  shop,  for  tools,  appliances 
and  practice  greatly  vary.  The  directions  given  here  are  therefore 
intended  merely  as  a  general  guide  and  will  not  necessarily  be  suit- 
able for  all  plants. 

OEGANIZATION. 

The  degree  of  organization  needed  in  a  drafting  office  depends 
upon  the  number  of  men  employed.  If  there  are  not  over  six  or 
eight,  little  or  no  organization  is  needed,  excepting  to  fix  the  office 


448  MILL  BUILDINGS 

hours  and  appoint  a  leader.  The  effect  of  consolidation  is,  how- 
ever, tending  to  collect  forces  into  greater  numbers,  and  most  struc- 
tural works  now  have  large  drafting  offices.  It  is  common  to  find 
structural  shops  using  from  fifty  to  one  hundred  draftsmen,  and 
then  organization  is  needed. 

Both  engineering  and  executive  ability  are  required.  It  was 
formerly  the  practice  to  select  one  man  as  the  leader,  and  to  depend 
on  him,  not  only  to  employ  men  and  manage  the  office,  but  also  to 
act  as  detail  engineer.  It  is  now  realized  that  these  two  kinds  of 
service  cannot  be  expected  in  any  great  degree  from  the  same  man, 
for  if  he  becomes  absorbed  in  making  economical  designs  he  will 
probably  neglect  executive  duties.  The  present  practice,  therefore, 
in  many  of  the  largest  works  is  to  have  two  heads  for  the  drafting 
department,  one  an  executive  or  superintendent,  and  the  other  an 
engineer  or  chief  draftsman. 

Under  these  heads  the  office  should  be  divided  into  parties,  each 
containing  four  to  eight  men,  who  will  work  unitedly  on  the  draw- 
ings for  separate  buildings,  but  will  not  interfere  with  other  parties. 
They  should  be  assembled  at  tables  adjoining  each  other,  and  one 
man,  known  as  "squad  foreman/'  selected  as  a  leader  for  each  party, 
who  will  have  charge  of  the  work. 

The  parties  will  contain  men  with  various  degrees  of  skill,  two 
or  three  being  competent  to  work  independently  in  laying  out  and 
designing  details,  while  the  rest,  known  as  tracers,  may  be  less 
experienced,  giving  their  time  chiefly  to  actually  making  the  finished 
drawings. 

There  must  also  be  checkers  for  verifying  drawings  after  they 
are  finished,  generally  one  of  these  men  for  each  party.  The  check- 
ers should  be  assembled  by  themselves  for  ease  in  consultation,  so 
their  work  will  be  done  uniformly.  They  should  work  under  the 
direction  of  the  chief  draftsman  and  not  in  any  of  the  squads,  to 
insure  greater  freedom  in  making  changes  where  desirable  or 
necessary. 

There  is  usually  some  machine  drawing  in  a  structural  draft- 
ing office,  in  connection  with  shop  cranes  or  other  mechanical 
appliances,  and  in  an  office  of  fifty  draftsmen  there  should  be 
one  or  two  mechanical  draftsmen,  and  all  drawings  for  the  machine 
shop  should  be  made  by  them.  In  an  office  of  this  size  there  should 
also  be  one  or  two  experienced  in  architectural  work,  for,  while 
mill  and  factory  buildings  are  not  usually  works  of  architecture,  it 
is  desirable  to  make  them  look  as  attractive  as  possible.  The  serv- 
ices of  these  men  may  also  be  needed  in  the  designing  and  estimating 


ORGANIZATION  OF  DRAFTING  OFFICE  449 

department,  in  tendering  for  large  building  contracts  containing 
architectural  design,  either  on  the  exterior,  or  interior  design  for 
offices. 

It  may  he  necessary  to  make  complete  architectural  drawings 
when  tendering  for  work,  and  contracts  are  sometimes  secured 
conditional  on  the  steel  contractor  supplying  free  of  charge  the 
complete  drawings  for  the  building.  At  other  times  when  tender- 
ing for  attractive  work  it  may  greatly  add  to  the  chances  of  getting 
it  if  the  proposal  is  accompanied  by  a  water  color  perspective  of  the 
building.  In  all  such  work  the  services  of  architectural  draftsmen 
will  be  of  great  value.  The  extra  expense  of  these  drawings  is 
small  in  comparison  to  the  prospective  profits. 

The  blue  printing  and  photographic  departments  will  need  the 
services  of  two  or  three  men  with  separate  rooms,  and  large  offices 
should  have  one  man  whose  duty  it  is  to  take  charge  of  and  file  all 
drawings  and  other  records.  There  should  also  be  two  or  three 
boys  for  messenger  service. 

In  an  office  of  fifty  men,  not  including  the  printing  department, 
messengers  and  filing  clerk,  there  will  be — 

1  Head  Draftsman, 

3  Mechanical  Draftsmen, 

1  Architectural  Draftsman, 

5  Checkers, 

5  Drafting  Squads  with  8  men  each. 

If  the  shop  contracts  for  structural  work  other  than  mill  and 
factory  buildings,  it  is  better  to  divide  the  office  into  two  depart- 
ments, giving  all  the  mill  buildings  to  one  department,  and  other 
structural  work,  such  as  that  for  office  buildings,  warehouses,  busi- 
ness blocks,  etc.,  to  the  other.  If  these  departments  are  large 
enough  to  warrant  it,  there  should  be  a  head  draftsman  appointed 
for  each. 

SUBDIVISION  OF  LABOE. 

It  is  economical  for  all  work  of  the  same  kind  to  be  done  as  far 
as  possible  by  the  same  men.  These  men  benefit  by  experience,  and 
mistakes  are  not  repeated.  Perhaps  the  greatest  benefit  that  is 
derived  from  the  subdivision  of  labor  is  that  the  various  shops 
become  accustomed  to  receiving  drawings  made  by  the  same  lot  of 
men,  and  the  shop  man  and  draftsmen  learn  to  better  understand 
each  others'  methods.  The  shop  men  become  familiar  with  the 
drawings  and  know  where  to  look  for  information,  because  of  the 


450  MILL  BUILDINGS 

uniformity  of  their  methods.  Subdivision  of  labor  is  the  source  of 
great  economy  in  production,  though  it  becomes  tiresome  to  the 
workmen,,  who  get  little  variety  or  change.  The  draftsmen  tire  of 
one  continuous  kind  of  work,  and  are  often  obliged  to  change  from 
one  office  to  another  to  relieve  the  monotony,  but  notwithstanding 
this,  most  large  offices  retain  the  system.  It  is  practiced  to  such  a 
degree  in  some  works  that  men  are  kept  continuously  working  on 
drawings  of  the  same  kind.  One  draftsman  will  make  drawings 
of  building  columns,  another  of  roof  trusses,  another  will  make 
bracing  drawings,  etc.,  each  becoming  so  accustomed  to  his  par- 
ticular work  that  it  is  made  easily,  uniformly  and  with  the  least 
number  of  mistakes.  The  system  has  proved  so  economical  that 
shops  adhere  to  it,  even  though  men  leave  and  new  ones  must  be 
employed.  Draftsmen  generally  prefer  to  work  in  small  offices,  for 
subdivision  of  labor  is  then  impractical  and  the  duties  of  the  men 
are  more  varied.  It  is  quite  common  for  men  in  a  large  office  to 
be  employed  for  a  year  or  more  making  drawings  of  the  same  kind, 
and  they  will  be  so  busily  engaged  that  they  may  not  have  time  to 
become  familiar  with  the  design  as  a  whole. 

THE  CHIEF  ENGINEER. 

The  chief  engineer  of  a  plant  usually  gives  his  principal  atten- 
tion to  the  designs  and  estimates,  and  his  work  is  referred  to  at 
greater  length  in  the  chapter  on  "Estimating." 

OFFICE  SUPERINTENDENT. 

The  duties  of  the  office  superintendent  are  to  employ  and  dis- 
charge men  and  see  that  work  in  the  office  is  being  carried  on  with 
the  greatest  economy.  He  must  see  that  men  are  employed  on 
work  to  which  they  are  best  suited,  judge  of  their  capabilities  and 
see  that  office  hours  are  enforced  and  employees  giving  good  service. 
He  should  keep  account  of  the  cost  of  drawings  made  by  different 
squads,  and  for  different  kinds  of  building.  The  superintendent 
should  see  that  the  office  is  working  in  harmony  with  the  estimating 
department  and  with  the  shops,  and  should  have  a  system  of  order 
blanks  for  the  various  departments  to  issue  on  each  other.  These 
written  orders  and  receipts  should  be  given  when  drawings  are 
received  and  delivered.  He  must  also  have  an  office  timekeeper, 
who  will  tabulate  the  time  spent  by  every  man  on  each  particular 
contract,  as  well  as  noting  any  days  that  the  men  are  absent.  These 
time  records  are  important  in  computing  the  cost  of  drawings  for 


ORGANIZATION  OF  DEAF  TING  OFFICE  451 

various  buildings.     The  rating  of  office  employees  will  be  fixed  by 
the  superintendent  and  he  will  arrange  vacations. 

HEAD  DRAFTSMAN. 

The  head  draftsman  must  receive  from  the  estimating  and  con- 
tracting department  all  available  data,  stress  sheets,  specifications, 
etc.,  relating  to  each  building  contract.  When  the  office  contains 
several  squads,  it  is  better  that  he  give  his  time  to  supervision.  He 
must  keep  careful  record  showing  when  all  orders  were  received, 
when  drawings  were  started,  when  completed,  and  the  date  when 
any  or  all  drawings  were  sent  to  the  shops,  that  he  may  know  on 
short  notice  what  progress  has  been  made  on  any  particular  contract. 
It  is  customary  to  have  a  great  many  building  contracts  under  way 
at  the  same  time,  and  without  a  detailed  record  it  would  be  diffi- 
cult to  make  quick  progress  reports.  A  convenient  record  book  for 
this  purpose  is  one  which  can  be  carried  in  the  pocket,  with  pages 
ruled  in  columns,  allowing  one  column  for  each  kind  of  informa- 
tion, with  one  horizontal  line  for  each  job.  It  is  possible  to  tabu- 
late a  large  amount  of  information  in  this  way  in  a  very  compact 
space.  When  this  is  kept  up  to  date,  the  head  draftsman  can 
report  at  once  the  progress  made  on  drawings  for  each  building. 
To  avoid  misunderstanding  the  head  draftsman  should  give  his 
orders  only  to  the  checkers  and  squad  foremen,  and  not  to  the 
members  of  the  squads.  While  his  duties  are  principally  in  con- 
nection with  the  drawings,  he  should  be  a  good  manager  and  leader, 
so  there  will  be  no  friction  between  the  men  under  his  direction. 
Contracts  may  be  secured  which  have  detail  drawings,  and  these 
details  must  be  examined  to  see  where  they  need  changing  to  suit 
shop  practice.  It  is  frequently  easier  to  have  such  details  redrawn 
than  to  change  several  sets  of  blue  prints.  All  contracts  received  in 
the  drafting  office  will  be  given  a  number,  and  the  head  draftsman 
must  see  that  data  papers  come  to  him  in  duplicate,  one  set  for  his 
own  record  and  the  other  for  the  squad  foreman.  All  instructions 
must  be  written.  The  head  draftsman  must  consult  with  squad 
foremen  and  checkers,  with  the  officers  of  the  company,  with  the 
contracting  department,  and  with  the  shop  foreman. 

SQUAD  FOREMAN. 

The  squad  foreman  will  receive  from  the  head  draftsman  all 
papers  and  data  relating  to  the  buildings  for  which  his  party  is  to 
make  the  drawings.  As  he  may  have  several  buildings  under  way 


452  MtLL  BUILDINGS 

at  the  same  time,  he  must  keep  separate  files  for  the  papers  relating 
to  each.  Spring  clips  are  convenient  for  this  purpose,  when  the 
files  are  not  too  large,  and  these  may  be  hung  on  the  wall  con- 
venient to  the  tables.  For  a  large  number  of  papers  ordinary  letter 
files  are  convenient.  He  must  keep  a  record  of  the  time  when  all 
papers  are  received,  when  drawings  are  completed,  the  number  of 
drawings  made  for  each  building,  and  amount  of  time  spent  by  men 
on  different  ones.  This  will  enable  him  to  keep  account  of  the 
work  under  his  direction.  Rivalry  between  the  squads  will  often 
result  in  a  greater  amount  of  work  being  done.  Verbal  instruc- 
tions must  be  written,  with  the  date  when  they  were  received,  and 
placed  in  their  proper  file.  Drawings  and  papers  of  every  descrip- 
tion must  be  dated ;  this  is  very  important,  as  claims  often  depend 
upon  the  dates  when  material  was  ordered  or  work  completed.  An 
experienced  draftsman  should  make  from  30  to  40  square  feet  of 
finished  drawings  per  week,  including  making  corrections  after 
they  are  checked;  a  beginner  will  make  not  more  than  half  that 
amount.  Drawings  for  ordinary  mill  buildings,  including  the  de- 
sign for  details,  order  bills  and  shop  lists,  should  not  cost  more 
than  $1  per  square  foot. 

The  squad  foreman  must  be  an  engineer,  able  to  design  all 
details  and  check  the  general  design  as  it  comes  from  the  estimating 
department.  He  must  make  the  general  sketches  from  which 
material  is  ordered,  and  either  order  the  material  or  check  the  list 
as  written  down  by  the  others.  If  time  will  permit,  he  should 
check  the  stress  sheets,  for  it  is  sometimes  economical  to  change 
certain  sizes  to  suit  better  details.  Squads  should  be  assembled 
by  themselves,  so  work  can  be  carried  on  with  the  least  amount  of 
traveling  about  the  office.  The  squad  foreman  should  give  his 
chief  attention  to  seeing  that  details  are  properly  designed  and 
drawings  made  economically.  If  he  is  unable  to  design  all  the 
details  himself,  he  must  see  that  they  are  properly  designed  by 
others,  or  when  not  employed  in  supervision,  must  himself  be  a 
worker.  The  cost  of  details  made  by  experienced  designers  may  be 
from  20  to  50  per  cent  less  than  those  made  by  less  experienced 
men,  chiefly  because  of  the  less  amount  of  metal  used.  It  is  there- 
fore very  important  to  have  this  work  properly  done  by  draftsmen 
who  understand  detail  design. 

Where  a  building  is  large  or  complicated  it  is  convenient  to 
have  the  general  drawings  traced,  and  provide  each  man  who  is 
working  on  the  drawings  writh  blue  prints.  Blue  prints  of  the  gen- 
eral drawing  should  also  be  sent  to  the  works  with  the  first  lot  of 


OEGANIZATION  OF  DRAFTING  OFFICE  453 

details,  in  order  that  the  shop  men  may  have  an  intelligent  idea  of 
what  they  are  making. 

Loose  leaf  books  are  preferable  to  others.  When  calculations 
are  completed  they  can  be  filed  away  with  other  papers  and  the 
books  used  again. 

•The  squad  foreman  must  know  the  capabilities  of  the  men  and 
what  work  he  can  safely  entrust  to  them.  He  must  see  that  no 
parts  or  details  be  shown  or  ordered  more  than  once. 


CHAPTER  LXV. 

DRAFTING  OFFICE  PRACTICE.* 

PRELIMINARY  SKETCHES. 

The  first  duty  of  the  squad  foreman  after  receiving  orders  to 
make  detail  drawings  for  a  building  is  to  prepare  preliminary 
sketches  complete  enough  for  ordering  material.  If  it  is  known 
that  the  required  stock  is  in  the  company's  yard  in  long  lengths,  it 
is  then  necessary  to  write  an  order  with  only  approximate  lengths, 
so  it  may  be  reserved  for  this  particular  building.  This  is  done 
only  when  the  work  must  be  completed  in  a  time  which  is  insuf- 
ficient to  have  special  material  delivered  from  the  mill  in  the 
lengths  needed.  If  long  stock  from  the  yard  must  be  cut,  the  pur- 
chaser must  generally  pay  a  higher  price  than  when  time  will  per- 
mit the  right  lengths  to  be  ordered  from  the  mill.  In  the  former 
case  there  will  be  waste  in  the  ends  that  are  cut,  for  a  portion  of 
which  the  purchaser  must  pay.  Some  of  the  cuttings  can  be  used 
for  details,  but  as  the  method  involves  waste  it  is  better  to  order  in 
exact  lengths  when  time  will  allow.  Some  designers  prefer  to  use 
two  different  scales  for  preliminary  sketches,  a  small  one  for  the 
general  outline  and  a  larger  one  for  the  joint  details.  A  uniform 
small  scale  of  one-half  inch  per  foot  has  the  advantage  over  the 
above  method  in  that  many  proportions  can  be  fixed  by  the  experi- 
enced eye  which  cannot  as  well  be  done  when  different  ones  are 
used.  Only  enough  drawing  need  be  done  on  preliminary  sketches 
to  determine  the  lengths  and  sizes  of  materials.  Joint  plates  must 
have  the  number  and  position  of  rivets  shown  to  scale.  The  rivets 
are  first  located,  spacing  them  not  less  than  three  diameters  of  the 
rivet  apart,  and  then  around  the  rivets  the  outline  of  a  plate  is 
drawn  which  will  contain  them.  The  size  and  allowable  shearing 
and  bearing  pressures  on  rivets  are  given  in  any  of  the  mill  hand- 
books. For  heavy  work  with  large  stresses  the  center  lines  of 
pieces  must  intersect  at  points,  but  members  with  small  stresses, 
the  joints  of  which  have  surplus  strength,  may  be  assembled  at  the 
panel  points  to  produce  the  most  compact  and  neat  arrangement, 


*  H.  G.  Tyrrell,  Engineering  News,  March  23,    1905. 

454 


DEAF  TING  OFFICE  PE  ACT  ICE 


455 


without  regard  to  center  lines.  When  the  sketches  are  started  right 
the  work  will  advance  smoothly,  but  if  commenced  wrong  there  is 
likely  to  be  confusion  until  it  is  finished.  Single  pieces  like  pur- 
lins may  be  ordered  directly  from  line  diagrams,  allowing  clearance 
at  the  joints.  A  stiffer  building  results  when  purlin  splices  are 
staggered  than  when  joints  are  all  at  the  same  panels. 

OKDEEING  MATEEIAL. 

In  ordering  material,  a  schedule  should  be  made  for  one  piece, 
and  the  total  number  of  pieces  given.  Parts  like  trusses,  sym- 
metrical about  the  center,  should  be  scheduled  by  listing  the  ma- 


Fig.   646. 

terial  in  one-half  the  truss,  giving  the  number  of  half  trusses. 
There  is  less  chance  for  error  in  this  way  than  when  the  total  num- 
ber of  pieces  is  written  at  first.  After  the  schedule  has  been  made 
for  all  the  pieces  it  should  be  recopied,  writing  all  material  of  the 
same  form  and  size  together  and  separating  soft  from  medium  steel. 
It  is  better  for  this  purpose  to  have  blank  forms  with  two  columns 
for  lengths — one  for  finished  lengths  and  another  for  lengths  in 
which  material  is  ordered,  which  may  contain  only  a  small  excess 
for  trimming,  or  may  be  in  long  pieces. 


Fig.  647. 

Beams,  channels  and  tees  are  ordered  by  weight  per  foot,  and 
all  other  shapes  by  width  and  thickness.  Weight  and  thickness 
should  not  both  be  given,  or  confusion  will  follow.  Short  pieces 
should  be  ordered  in  long  lengths  not  exceeding  40  to  50  feet  for 
large  angles  or  30  feet  for  smaller  ones  which  might  bend  when 
handling.  Plates  should  not  generally  be  ordered  longer  than  20 
feet,  for  greater  lengths  are  difficult  to  handle  and  can  be  raised 
only  on  a  stiff  frame  or  lifting  piece.  Irregular  shaped  connec- 
tion plates  should  be  ordered  in  multiple  lengths  with  edges  alter- 
nating, as  shown  in  Fig.  646.  Widths  of  plates  should  always  be 


456  MILL  BUILDINGS 

given  in  inches.  If  ends  of  pieces  are  to  be  milled,  the  material 
should  be  ordered  one-fourth  inch  long  for  each  end  so  finished. 
An  extra  charge  is  made  by  the  mill  if  beams  and  channels  are 
required  in  lengths  with  less  variation  than  f  inch  either  way. 
Therefore,  for  ordinary  work,  beams  and  channels  should  be  ordered 
J  inch  shorter  than  the  panel  lengths.  In  ordering  rods  or  eye  bars 
requiring  heads,  allowance  should  be  made  for  the  extra  length 
needed  in  forming  them.  The  mills  which  make  eye  bars  give  the 
extra  length  required  for  forging  heads  in  their  machines.  If 
plates  are  to  be  heated  and  bent,  some  allowance  should  be  made 
for  trimming  the  plate  afterwards,  as  it  may  not  bend  exactly  to 
the  line.  Long  plates  which  must  be  straight  on  the  edges,  such  as 
girder  covers,  are  called  Universal  Mill  and  must  be  so  marked 
on  the  order.  Turned  pins  are  ordered  TV  inch  larger  than  the 
finished  size,  but  small  bracing  or  cotter  pins  are  usually  made  of 
cold  rolled  shafting  and  ordered  in  exact  size.  Corrugated  iron  is 
made  in  even  lengths  from  4  to  8  feet.  In  ordering  matched  lum- 
ber over  one  inch  in  thickness,  from  one-fifth  to  one-sixth  should 
be  added  for  the  tongues.  Beams,  channels  or  angle  purlins  that 
require  only  a  small  amount  of  shop  work,  perhaps  no  more  than 
punching,  should  be  shipped  directly  from  the  mill  to  the  building 
site,  thereby  saving  freight. 

MASONEY  PLAN. 

After  the  preliminary  sketches  have  been  made  and  the  material 
order  written,  the  ground  plan  should  be  drawn  so  the  foundations 
can  be  built  to  suit  the  prospective  building.  Unless  the  steel  con- 
tract includes  the  foundation,  which  is  rarely  the  case,  it  will  be 
necessary  to  show  only  enough  on  the  plan  to  enable  the  owner  or 
local  builder  to  make  them  fit  the  steel.  The  location  of  walls  and 
piers  should  be  shown,  and  a  detail  drawn  for  one  pier  indicating 
the  exact  position  of  the  anchor  bolts  in  reference  to  its  center. 
If  the  walls  have  steel  columns,  a  detail  should  be  drawn  with  a 
general  scale  of  J  or  J  inch  per  foot,  with  other  details  to  a  larger 
scale.  The  general  dimensions  must  all  be  given.  A  copy  of  this 
should  be  sent  to  the  owner  or  local  builder.  If  the  steel  contract 
includes  the  foundations,  a  complete  plan  should  be  drawn  with  all 
details  thereon. 

LAYING  OUT  WOEK. 

If  the  design  is  simple,  the  preliminary  sketches  used  in  ordering 
material  may  be  a  sufficient  guide  for  the  detailers,  but  when  build- 
ings are  complicated,  further  general  drawings  are  needed.  It  is 


DRAFTING  OFFICE  PRACTICE  457 

important  to  start  correctly,  for  it  is  easier  to  redraw  an  entire  sheet 
than  to  make  the  corrections  on  a  drawing  that  was  wrongly  laid 
out.  It  is  easier  to  lay  out  simple  work  directly  on  the  cloth,  using 
pencil  as  little  as  possible,  than  to  draw  on  paper  and  then  trace. 
In  many  cases  lines  can  be  drawn  at  once  in  ink  with  a  great  saving 
in  time.  More  difficult  work  requiring  much  study  must  be  drawn 
and  figured  first  on  paper,  for  too  many  changes  and  erasures  would 
be  needed  if  this  kind  of  work  were  put  directly  on  cloth.  The 
connections  are  the  first  to  be  detailed  when  starting  a  layout,  and 
these  parts  may  be  indicated  in  red  ink  on  the  detail  drawing  for 
the  purpose  of  showing  clearances.  After  connections  are  detailed 
the  balance  of  the  member  can  be  elaborated.  If  the  process  were 
reversed  and  the  connections  left  until  the  last,  it  would  then  be 
found  that  many  minor  details  which  could  just  as  well  have  been 
made  in  some  other  way,  interfere  with  the  joints  and  must  be 
changed.  Purlins  should  be  located  to  suit  standard  lengths  of 
sheathing,  allowing  a  4-inch  lap  for  corrugated  iron  on  the  sides  of 
buildings  and  6-inch  lap  on  the  roof.  Widths  of  roof  monitors 
should  be  made  to  suit  some  even  length  of  sheet  from  4  to  8  feet. 
It  must  be  remembered  in  laying  out,  that  the  maximum  sizes 
accepted  by  the  railroad  companies  for  shipping  are  widths  up  to 
8  feet,  heights  up  to  10  feet,  and  lengths  for  ordinary  cars  of  30  to 
40  feet.  In  special  cases,  long  girders  may  be  shipped  on  two  cars 
with  a  spacer  car  between  them.  In  this  way  girders  of  over  100 
feet  in  length  may  be  loaded.  It  simplifies  calculations  to  assume 
rivet  values  in  round  numbers,  making  gussets  thick  enough  so  the 
bearing  value  of  rivets  in  the  plate  will  at  least  equal  the  shearing 
value  of  the  rivet.  It  is  close  enough  to  assume  working  values  of 
rivets  £ ,  f  and  £  inch  diameter  as  2,000,  3,000  and  4,000  pounds, 
respectively.  The  results  are  quite  as  good  with  much  less  labor 
as  when  values  are  assumed  in  exact  units.  Stiff  members  must  be 
used  wherever  possible.  The  practice  of  using  flat  bars  for  the 
tension  members  of  roof  trusses  is  wrong,  for  they  do  not  hold  their 
shape  when  handled,  and  when  once  bent  are  seldom  straightened. 
Work  should  be  laid  out  so  shop  rivets  can  be  used  in  preference  to 
field  rivets  or  bolts.  Shop  rivets  costing  2  cents  each,  would  cost  5 
cents  if  field  riveted  under  favorable  circumstances.  In  wide  angles 
with  two  or  more  rows  of  rivets  in  each  leg,  it  is  better  to  place  the 
rivets  in  the  two  legs  opposite  each  other,  rather  than  make  any 
effort  at  staggering,  the  inner  row  in  one  leg  being  opposite  the 
outer  row  of  the  other.  This  will  prevent  interference  when  driv- 
ing and  save  much  time  that  would  be  consumed  in  figuring  exact 


458 


MILL  BUILDINGS 


stagger.  Moreover,  there  is  no  section  area  saved  by  alternating 
in  angles  having  two  or  more  rows  in  each  leg.  The  method  of 
placing  rivets  opposite  each  other  has  the  advantage  of  preventing 
the  rivets  from  interfering  with  outstanding  legs  of  stiffening 
angles,  as  happens  when  the  rivets  in  one  flange  stagger  with  those 
in  the  other  flange.  If  there  is  only  one  row  of  rivets  in  each 
flange,  it  will  then  he  better  to  alternate  the  rivets,  for  placing  them 
opposite  cuts  out  too  great  an  area  from  the  angles.  When  rivets 
alternate,  the  stagger  should,  for  appearance  sake,  be  exact. 

Wherever  possible,  rivets  should  be  symmetrical  about  a  center 
line,  for  half  templets  may  then  be  used  with  a  proportionate 
saving  in  expense.  Bracing  should  be  stiff,  as  rods  sag  and  rattle 


Fig.   648. 


Fig.  649. 


when  loose.  Simple  angles  may  be  used  for  roof  purlins  in  lengths 
up  to  15  feet,  but  from  15  to  20  feet  they  should  be  trussed,  prefer- 
ably with  a  light  angle.  Purlins  should  be  bolted  to  the  trusses 
and  fastened  through  clips,  rather  than  directly  to  the  rafters.  An 
essential  in  designing  details  is  to  make  the  joints  stiff  and  have  the 
whole  frame  well  braced  and  rigid.  If  more  than  three  rivets  are 
used  in  the  end  of  a  piece,  it  is  better  to  use  lock  angles  and  fasten 
the  members  by  both  legs.  One  size  of  rivets,  especially  for  field 
joints,  is  preferable  to  several.  It  is  better  to  increase  the  dimen- 
sions of  a  few  members  than  to  use  several  rivet  sizes,  requiring 
material  to  be  moved  about  to  different  punching  machines.  When 
rivets  resist  direct  stress,  as  those  at  truss  joints,  it  is  economical 
to  use  larger  ones  because  fewer  will  then  be  needed,  but  when 


DRAFTING  OFFICE  PRACTICE  459 

they  are  merely  stitch  rivets  for  holding  parts  together,  it  is  better 
to  use  smaller  ones.  Stitch  rivets  have  very  little  stress  upon  them 
and  small  ones  are  easier  to  drive.  The  work  should  be  designed 
so  there  will  be  the  least  number  of  hand  driven  rivets.  Joints 
should  be  made  so  that  they  can  be  bolted  up  during  erection  and 
made  secure  in  the  shortest  possible  time.  Trusses  40  feet  in  length 
or  less  should  usually  be  shipped  loose,  with  only  the  connections 
and  detail  parts  shop  riveted  to  the  members.  The  minimum 
freight  charge  for  an  entire  car  is  for  a  weight  of  30,000  pounds. 
The  partial  carload  rate  is  higher  per  pound,  but  the  weight  to  be 
shipped  may  be  so  small  that  a  net  saving  will  result  by  sending  it 
loose. 

Joint  plates  such  as  those  used  in  trusses  should,  wherever 
possible,  be  made  symmetrical,  and  this  can  generally  be  done  by 
using  a  little  care  in  locating  the  splice.  Fig.  648  shows  a  common 
way  of  detailing  joint  plates  by  splicing  the  truss  chord  at  the  panel 
point,  but  by  moving  the  splice  slightly  to  the  right,  as  shown  in 
Fig.  649,  a  symmetrical  plate  results  which  has  a  much  better  ap- 
pearance. Pin  plates  must  have  enough  rivets  to  safely  transmit 
the  pressure  on  them  from  the  pin  into  the  chord  section  through 
shearing  on  the  pin  plate  rivets.  The  thickness  of  plates  must  be 
great  enough  so  the  safe  bearing  pressure  on  pins  will  not  be 
exceeded.  Roof  purlins  at  the  gables  must  be  either  bolted  to  a 
continuous  angle  at  the  wall  or  have  separate  anchors  or  hooks 
holding  them  to  the  brickwork.  When  the  purlins  overhang  the 
ends  of  the  building,  there  should  be  a  fascia  or  finish  angle  cover- 
ing the  purlin  ends  and  the  unprotected  edge  of  the  corrugated 
iron.  At  the  eave,  for  both  brick  and  corrugated  iron  walls,  there 
should  be  a  strut  joining  the  tops  of  the  columns.  When  bays 
exceed  15  feet  in  length,  there  should  be  rods  f  or  J  inch  in  diameter 
between  the  purlins  to  prevent  them  from  sagging.  Members  com- 
posed of  two  channels  should  have  the  flanges  turned  out  to  allow 
the  rivets  to  be  machine  driven,  for  if  turned  in,  it  may  be  difficult 
to  insert  the  arm  of  a  machine.  Hand  riveting  is  more  expensive 
and  not  as  satisfactory  as  power  driving.  Struts  composed  of  two 
angles  placed  back  to  back  should  be  united  by  stitch  rivets  from  3 
to  4  feet  apart.  Roof  trusses  should  be  cambered  not  less  than  2 
inches  in  every  100  feet,  and  the  amount  of  camber  should  be 
marked  on  the  drawing  at  every  panel  point.  Standard  size  sheets 
will,  on  an  average,  require  from  two  to  three  days  for  laying  out 
and  making  ready  for  tracing. 


460  MILL  BUILDINGS 

TKACING  DEAWINGS. 

The  finished  drawing  is  the  final  result  of  the  engineering  and 
drafting  departments,  and  it  is  therefore  important  that  it  be  neatly 
and  carefully  made.  Some  offices  still  use  the  services  of  beginners 
for  tracing,  while  others  prefer  a  higher  grade  of  men  for  this 
work,  the  latter  being  the  better  plan.  It  is  folly  for  experienced 
engineers  to  spend  valuable  time  in  perfecting  designs  and  carefully 
laying  out  working  drawings,  and  then  permit  beginners  to  trace 
these  drawings  so  poorly  that  much  of  their  meaning  is  lost.  It  is 
better  to  have  the  men  who  made  the  drawings  trace  their  own 
work,  and  use  assistants  only  for  putting  on  printing  and  figures. 
It  is  preferable  to  detail  pieces  in  the  position  which  they  will 
occupy  in  the  building,  columns  being  vertical,  girders  horizontal, 
etc.  The  top  view  of  a  piece  should  be  placed  above  it  in  its  natural 
position  and  the  bottom  view  below  the  elevation,  but  top  and  bot- 
tom views  should  not  be  combined  in  one,  as  it  is  confusing.  It  is 
better  to  spend  more  time  in  drawing  separate  views  than  to  take 
chances  on  causing  errors.  Center  and  dimension  lines  should  be 
fine  black,  of  uniform  thickness,  but  full  enough  for  printing.  Red 
ink  should  never  be  used  on  tracings  excepting  for  connections  and 
for  checking  marks.  It  shows  only  faintly  on  blue  prints  and  not 
plain  enough  for  the  principal  drawing.  Lines  showing  the  picture 
of  a  piece  should  be  solid  but  not  so  heavy  that  clearness  in  detail 
is  lost.  When  drawings  are  copied  by  the  photograph  process,  lines 
must  be  heavier  than  is  permissible  for  blue  printing,  because  in 
photo  reproduction  the  thickness  of  lines  is  reduced  in  proportion  to 
the  reduction  of  the  drawing.  The  style  of  lettering  should  be 
small  block,  inclined  for  greater  ease  in  making  at  a  slight  angle 
to  the  vertical.  The  letters  should  be  about  -J  inch  high  and  made 
with  a  fairly  coarse  pen.  In  writing  letters  and  figures,  care  must 
be  taken  to  make  them  open,  so  adjoining  lines  will  not  run  together 
and  form  blots.  Letters  indicating  assembling  and  shipping  marks 
should  be  larger  and  more  pronounced,  and  from  -f^  to  J  inch 
high. 

In  the  upper  left  hand  corner  there  should  be  a  small  dia- 
gram of  the  whole  building  frame  drawn  in  fine  black  lines,  with  the 
particular  part  detailed  on  that  sheet  emphasized  in  heavy  black. 
This  diagram  allows  the  eye  to  see  at  once  without  reading  the 
title  of  the  drawing,  the  location  of  the  piece  detailed.  Where  there 
is  doubt  about  details,  notes  on  the  drawing  will  often  add  clear- 
ness, but  should  not  be  made  to  take  the  place  of  drawings.  Some 
offices  make  a  practice  of  so  burdening  drawings  with  notes  that  it 


DRAFTING  OFFICE  PRACTICE  461 

is  difficult  to  know  the  actual  detail  from  some  other  piece  which 
is  not  shown  but  described.  It  is  clearer  to  make  a  new  drawing, 
-showing  the  other  piece,  than  to  try  reading  it  from  notes  on  a 
piece  which  it  resembles.  Doubt  about  the  makeup  of  a  piece  can 
be  removed  by  showing  a  cross  section.  Sections  at  one  end  of 
members  are  one  of  the  best  means  of  making  drawings  plain,  and 
should  be  freely  used.  Cloth  and  paper  are  cheaper  than  time 
spent  in  deciphering  obscure  details,  and  extra  sketches  should 
always  be  added  where  needed.  Particulars  in  reference  to  ream- 
ing, painting,  size  of  holes,  distinction  between  bolts  and  rivets,  or 
other  information  which  cannot  easily  be  shown,  should  be  described 
by  notes.  _ 

Only  three  or  four  standard  sizes  of  sheets  should  be  used,  the 
regular  one  being  24  by  36  inches.  Other  convenient  sizes  are  18 
by  24,  and  12  by  18  inches,  or  one-half  and  one-fourth  the  regular 
sheets.  Each  sheet  should  have  a  fine  border  line  about  one  inch 
from  the  trimming  edge.  This  gives  the  drawing  a  finished  appear- 
ance and  shows,  when  printed,  that  no  parts  are  missing.  These 
lines  should  not  be  heavy,  for  they  would  then  detract  attention 
from  the  essential  part.  If  there  are  many  sheets  to  be  joined 
they  should  be  lettered,  and  a  diagram  put  on  one  sheet  showing 
the  method  of  assembling  them.  It  is  convenient  to  make  casting 
drawings  not  larger  than  12  by  18  inches,  and  to  place  prints  of 
them  in  a  loose  leaf  book  for  future  reference.  The  loose  leaf  file 
allows  parts  to  be  arranged  in  subjects,  and  when  castings  are 
needed,  the  draftsman  should  see  whether  drawings  previously  made 
for  other  contracts  can  be  used  again,  thereby  saving  the  expense 
of  new  drawings  and  patterns.  This  casting  book  should  be  kept 
in  the  drafting  office,  where  it  may  be  consulted  freely  without  loss 
of  time. 

On  the  lower  right  hand  corner  of  each  sheet  should  be 
placed  the  title  of  the  drawing,  name  of  the  manufacturing  or  engi- 
neering company,  contract  number,  sheet  number,  total  number  of 
sheets  in  the  set,  date,  and  name  or  initials  of  the  men  who  made 
and  checked  the  drawing.  These  data  will  appear  more  uniform 
when  put  on  with  rubber  stamps,  but  as  india  ink  cannot  be  used 
with  stamps,  the  letters  on  the  tracing  cloth  must  be  blackened  with 
drawing  ink.  A  title  as  described  above  is  shown  in  Fig.  650.  The 
contract  number,  by  which  the  work  is  known,  rather  than  by  the 
name,  should  be  printed  in  large  figures  so  it  will  at  once  be  evi- 
dent. Most  large  drafting  offices  have  small  printing  presses  for 
putting  on  titles  or  notes  which  are  repeated  on  several  sheets.  The 


462  MILL  BUILDINGS 

printing  is  more  quickly  done  with  a  machine  and  looks  better  than 
hand  work.  Several  sheets  may  be  printed  at  one  time,  when  the 
drawings  are  completed.  When  pieces  are  right  and  left,  it  is 
understood  that  the  one  shown  is  the  right  hand  piece,  and  the 
other  one  is  the  left  hand.  The  words  right  and  left  have  no 
reference  to  the  right  and  left  sides  of  the  building,  but  simply 
denote  that  the  pieces  are  in  pairs.  It  is  frequently  possible  to 
avoid  making  rights  and  left  by  simply  countersinking  or  driving  a 
few  more  rivets,  or  making  some  other  minor  change,  which  may  be 
unnecessary  excepting  for  this  purpose.  The  extra  expense  is  war- 
ranted, for  it  may  avoid  serious  errors  during  erection.  It  is  a 
common  mistake  in  erection  to  put  right  hand  pieces  where  left 
hand  ones  belong,  and  this  may  often  be  avoided  by  a  little  addi- 


BUILT  BY 

THE  SMITH  -JONES  STRUCTURAL  Co. 
CHICAGO,  ILL. 


DRAWN  BY  .  .  .    M7s..  ...................  SHEET  NO.J8.  . 

yyi  "z>"7  —  -x  -c- 

CHECKED  BY.  .  ./V:4xW,/,.  ......  .  ............  OF33.  .  SHEETS 

SCALE  .....  3^!.^!  FOOT.  ...............  DATEtfafZffr 

CONTRACT  No.  3745 


Fig.  650. 

tional  shop  work.  The  number  of  parts  required  should  be  marked 
below  each  piece  in  letters  about  -j3^  inch  high.  In  giving  dimen- 
sions, the  draftsman  should  consider  what  ones  he  would  need, 
were  he  the  shop  work  man  about  to  make  the  piece,  and  then  give 
these  dimensions  and  no  more.  Tracings  should  be  made  on  the 
dull  side  of  the  cloth,  and  if  the  ink  will  not  run  smoothly,  the 
cloth  should  be  rubbed  well  with  powdered  chalk  and  then  wiped 
clean  with  a  soft  cloth.  Each  drawing  should  be  complete  in  itself, 


DRAFTING  OFFICE  PEACTICE  463 

and  reference  from  one  sheet  to  another  should  not  be  necessary. 
As  drawings  are  the  final  product  of  the  drafting  office  and 
expensive,  blue  prints  should  be  made  from  them  and  the  original 
tracings  filed.  Changes  on  cloth  must  be  made  with  soft  ink 
erasers,  and  never  with  a  knife  or  sharp  instrument.  Fractions 
should  be  written  with  horizontal  rather  than  with  oblique  lines, 
to  avoid  any  possibility  of  confusing  such  fractions  as  1%6  with 
IYQ.  Section  views  should  be  hatched  or  blackened,  and  when 
several  blackened  parts  join  each  other,  white  lines  or  spaces  must 
be  left  between  them.  Holes  for  field  bolts  and  rivets  should  be 
blackened.  Sheets  should  be  numbered  in  the  order  in  which 
material  is  required  at  the  building,  the  foundation  plan  being 
Number  1,  column  Xumber  2,  etc.  Many  dimensions  on  compli- 
cated trusses  may  be  omitted,  for  such  trusses  will  be  laid  out  on 
the  templet  shop  floor,  and  the  position  of  rivets  will  be  deter- 
mined from  the  layout  rather  than  from  the  drawings.  Details 
for  different  shops  should  be  kept  on  separate  sheets,  forgings  on  a 
sheet  for  the  forge  shop,  machine  parts  on  another  sheet  for  the 
machine  shop,  etc.  Standard  beam  and  channel  framing  as  given 
in  mill  handbooks  should  be  used  wherever  possible.  Clevises,  turn- 
buckles,  forkeyes,  loop  rods,  pins,  washers,  etc.,  should  be  shown 
on  standard  blanks  printed  on  strong  linen  paper,  thin  enough  for 
blue  printing  and  strong  enough  for  erasures.  Blank  forms  are 
also  used  for  the  different  kinds  of  framed  beams  and  channels. 
These  blanks  are  either  letter  or  cap  size,  8  by  10  or  8  by  13  inches, 
and  they  are  a  great  saving  in  time,  as  it  is  necessary  only  to  write 
in  the  figures  without  any  drawing.  An  extra  blank  may  be  used 
for  miscellaneous  sketches  to  be  filled  in  free  hand.  Some  of  these 
forms  are  shown  in  Figs.  242  and  243. 

MASKING  DEAWINGS. 

There  are  two  kinds  of  marks  used  on  shop  drawings,  assembly 
and  erection  marks.  The  former  are  wholly  for  the  use  of  men  in 
the  assembly  shop,  and  it  is  preferable  to  have  them  written  on  the 
templet  shop  blue  prints  with  yellow  pencil,  and  the  prints  passed 
on  to  the  assembly  shop.  Assembly  marks  are  sometimes  written 
on  the  tracings,  and  similar  parts  should  then  be  similarly  indicated. 
Truss  members  would  be  Tl,  T2,  T3,  etc.,  gusset  plates  Gl,  G2,  G3, 
etc.,  angle  clips  Cl,  C2,  C3,  etc.  Only  pieces  that  are  exact  dupli- 
cates should  be  stamped  the  same.  The  shipping  marks  of  indi- 
vidual pieces  serve  also  for  assembly  and  all  parts  that  are  shipped 
separately,  must  have  a  different  erection  mark.  Letters  R  and  L 


464  MILL  BUILDINGS 

refer  to  pieces  which  are  right  and  left  and  should  be  written  after 
the  regular  signs. 

CHECKING. 

There  should  be  one  checker  for  each  squad.  When  drawings 
have  been  carefully  made  by  men  who  understand  their  work,  little 
will  be  needed.  The  principal  trouble  in  checking  is  in  overhauling 
work  done  by  inexperienced  men. 

The  several  checkers  in  an  office  should  be  assembled  by  them- 
selves, so  they  may  compare  notes  with  each  other  and  work  more 
uniformly.  They  should  work  under  the  direction  of  the  head 
draftsman  rather  than  in  the  squads,  for  they  will  then  have  greater 
liberty  in  making  changes  if  such  are  desirable.  Some  offices  have 
the  false  idea  that  money  is  saved  by  employing  low  priced  drafts- 
men, whereas  records  made  by  the  writer  show  that  drawings  by 
inexperienced  men  cost  more  than  twice  as  much  in  actual  wages 
as  those  made  by  experienced  men  who  know  their  business  and 
are  better  paid.  To  this  difference  must  be  added  the  extra  cost  of 
checking  poor  drawings,  and  the  additional  cost  of  working  from 
them  in  the  shop.  It  has  been  conclusively  proven  that  money 
spent  in  making  drawings  that  are  neat,  plain  and  accurate  is  saved 
many  times  over  before  the  work  is  completed.  Especially  is  this 
true  in  reference  to  checking.  If  the  joints  are  complicated  it  is 
better  to  make  a  separate  layout  showing  all  rivets,  to  a  size  which 
can  be  safely  scaled.  Nothing  must  be  assumed  in  checking,  but 
everything  investigated.  It  is  especially  important  that  field  con- 
nections be  correctly  drawn,  as  errors  discovered  during  erection 
cause  greater  expense  than  if  found  before  the  pieces  have  left  the 
shop.  The  holes  in  pieces  for  field  connections  must  correspond 
and  be  the  same  size.  Sections  must  be  compared  with  the  stress 
sheets  to  see  that  the  correct  ones  are  used.  A  drawing  should  never 
be  checked  by  the  man  that  made  it.  After  figures  have  been  veri- 
fied they  should  be  marked  with  a  lot  of  red  ink,  for  red  will  print 
but  faintly  and  will  not  rub  off  when  the  drawing  is  being  cleaned. 
Corrections  should  be  marked  with  a  blue  pencil,  and  new  figures 
placed  far  enough  away  from  the  old  ones  so  they  will  not  be  erased. 
The  blue  pencil  marks  will  not  print,  are  plainly  seen,  and  easily 
cleaned  off. 

The  following  points  should  be  considered  when  verifying  draw- 
ings and  they  should  be  checked  as  to — 

(1)  Size  of  material  compared  with  stress  sheet. 

(2)  Size  of  holes  for  connecting  parts. 


DBAFTING  OFFICE  PRACTICE  465 

(3)  Number  of  field  rivets  at  joints. 

(4)  Beaming  or  drilling  of  field  connections. 

(5)  Number  of  main  pieces  required. 

(6)  Eight  or  left  of  shipping  pieces. 

(7)  Center  lengths. 

(8)  Milling  of  ends  if  needed. 

(9)  Bevels  for  mitered  joints. 

(10)  Need  of  countersinking. 

(11)  Insertion  or  driving  of  field  rivets  or  bolts. 

A  checking  list  of  building  parts  such  as  given  in  Chapter  XL 
should  be  reviewed  to  see  that  all  matters  have  received  attention, 
and  all  needed  parts  called  for  on  the  shipping  list. 

CORRECTING  DRAWINGS. 

In  order  to  have  a  drawing  checked  or  verified,  two  persons 
must  agree  upon  all  of  its  details  and  particulars.  It  must,  there- 
fore, be  an  absolute  rule  that  no  changes  shall  be  made  until  the 
maker  and  the  checker  have  agreed.  Some  shops  permit  checkers 
to  make  changes  on  plans  without  having  the  changes  sanctioned 
by  the  maker,  but  such  drawings  are  really  not  checked  at  all,  and 
are  little  better  than  when  reviewed  only  by  the  men  who  made 
them.  Blue  pencil  marks  must  be  left  on  the  tracings  and  not 
removed  until  the  checker  has  again  examined  them,  for  if  they 
are  erased  he  will  have  no  means  of  knowing  whether  the  correc- 
tions have  been  made  or  not.  When  tracings  have  been  altered' 
and  changes  approved  by  the  checker,  the  drawings  should  be 
cleaned  with  wool  or  waste  saturated  with  gasoline  or  benzine, 
which  should  be  kept  in  an  automatic  self-sealing  metal  bottle. 

CHANGING  SHOP  PRINTS. 

When  changes  are  needed  on  drawings,  prints  of  which  have 
gone  into  the  shop,  the  prints  must  either  be  collected  and  returned 
to  the  office  for  correction,  or  a  draftsman  must  go  through  the 
shops  and  make  the  alteration  on  the  prints  with  ink,  marking  each 
one  with  the  date  when  changes  were  made.  The  tracings  must  be 
similarly  changed  and  dated,  and  immediately  corrected  when  dis- 
covered, inquiry  being  made  to  find  if  any  work  has  been  done  on 
the  parts  affected. 

LISTING. 

There  must  be  a  bill  of  material  for  each  separate  shipping 
piece  in  order  to  know  what  parts  to  bring  into  the  assembling 


466  MILL  BUILDINGS 

shop.  This  bill  should  list  the  largest  pieces  first,  with  detail  parts 
later.  There  must  be  two  columns  for  lengths,,  one  for  the  finished 
length,  and  the  other  for  the  length  in  which  the  material  was 
ordered.  If  ordered  in  long  lengths,  it  may  contain  only  a  small 
excess  for  trimming  or  milling.  Where  assembly  marks  are  given, 
there  should  be  a  separate  column  for  these  in  the  bill.  It  is  con- 
venient to  write  the  bill  of  material  on  the  drawing,  though  some' 
shops  prefer  to  use  small  separate  forms.  There  must  also  be  a  set 
of  rivet  and  bolt  lists,  showing  in  detail  the  size  and  length  of  bolts 
and  rivets  for  all  joints,  with  marks  showing  parts  which  they 
connect.  These  lists  should  have  one  column  for  the  grip  and 
another  for  the  total  length  beneath  the  heads.  After  they  are 
completed,  a  summary  of  rivets  and  bolts  should  be  made  and 
written  on  a  separate  summary  sheet.  As  there  is  usually  some 
loss,  and  the  lengths  listed  are  not  always  used  where  they  belong, 
there  should  be  about  20  per  cent  more  bolts  and  rivets  shipped 
than  are  actually  needed,  the  ones  not  used  being  returned. 

A  shipping  list  should  be  made,,  giving  the  marks  of  all  the 
separate  pieces  with  the  size  and  a  brief  description.  On  this  should 
be  written  all  the  structural  steel  members,,  corrugated  iron,  flash- 
ing, gutters,  lumber,  conductors,  bolts  and  rivets,  tools,  spikes,  rail- 
ings, doors,  windows,  shutters,  and  all  other  articles  needed  to 
completely  erect  the  building.  It  is  very  important  that  all  pieces 
be  placed  on  the  shipping  list,  as  express  charges  are  high  on  addi- 
tional parts  which  may  have  been  forgotten.  Lists  should  not  be 
made  until  after  the  drawings  are  completed,  for  changes  on  them 
may  seriously  affect  the  lists  or  require  them  to  be  made  over.  Truss 
sections  can  be  most  easily  identified  by  small  free-hand  sketches 
with  extreme  dimensions.  Lateral  plates  projecting  from  the  side 
of  trusses  or  girders  should  be  sent  loose,  as  they  are  liable  to  be 
broken  if  shipped  in  place.  Loose  fillers  should  be  avoided  and 
should  be  tack  riveted. 

COPYING  LISTS. 

Lists  are  more  quickly  copied  when  written  with  ink  made  for 
printograph  blocks  than  when  blue  printed.  A  dozen  copies  can 
be  made  on  one  of  these  blocks  in  five  minutes,  which  might  require 
an  hour  to  print. 

ERECTION  DRAWINGS. 

The  erection  drawing  is  a  skeleton  outline  on  which  is  indicated 
the  shipping  marks  of  separate  pieces,  length  and  position  of  corru- 
gated iron,  flashing,  gutters,  and  all  other  parts  going  into  the 
building.  Bars  and  rods  are  described  by  their  size  and  length, 


DRAFTING  OFFICE  PEACTICE  4(57 

while  pins  are  stamped  with  a  mark  on  their  ends.  All  general 
dimensions  must  be  given,  and  expansion  joints,  if  any,  must  be 
shown.  Directions  must  also  be  given  for  the  final  painting,  color, 
number  of  coats,  etc.  On  this  sheet  there  should  also  be  a  table 
of  all  the  drawings  and  their  titles.  As  erection  labor  is  done 
under  unfavorable  circumstances  and  field  errors  are  expensive, 
care  should  be  taken  to  have  the  erection  drawings  as  complete  as 
possible.  If  it  is  discovered  during  erection  that  some  pieces  have 
been  made  too  long,  these  may  have  to  be  sent  back  to  the  shop, 
and  perhaps  delay  the  work  several  days,  awaiting  their  return. 
The  cost  of  erection  often  varies  from  20  to  30  per  cent,  depending 
upon  the  quality  of  the  drawings,  accuracy  of  shop  work  and  other 
conditions.  The  plan  should  show  the  direction  of  column  webs, 
the  way  channels  turn,  and  all  other  information  that  the  erection 
men  will  need.  Field  riveting  of  trusses  when  required,  is  cheapest 
when  done  on  the  ground,  for  if  rivets  are  driven  with  the  truss 
erected  in  position,  the  cost  may  increase  from  five  cents  to  twenty- 
five  cents  per  rivet,  owing  to  the  need  of  temporary  staging.  No 
staging  is  required  when  pieces  are  bolted  in  position. 

FILING  DEAWINGS  AND  LISTS. 

Drawings  should  be  laid  out  flat  in  drawers  and  not  rolled,  for 
after  being  rolled  they  are  difficult  to  handle.  Lists  may  be  kept 
in  ordinary  letter  files  in  the  order  of  contract  numbers.  Some 
shops  make  a  practice  of  filing  drawings  of  similar  buildings  in 
drawers  by  themselves,  but  it  is  better  to  have  contract  numbers 
consecutive.  Other  shops  number  all  drawings  in  numerical  order, 
instead  of  marking  each  separate  set  of  drawings  upward  from 
Number  1.  The  drawers  in  which  they  are  filed  should  be  about 
30  by  40  inches  inside,  so  occasional  ones  of  a  larger  size  than  24 
by  36  can  be  included. 

COPYING  DEAWINGS. 

The  method  almost  exclusively  used  for  copying  drawings  is 
blue  printing.  White  prints  are  made  by  first  making  Van  Dyke 
negatives,  but  they  require  twice  the  time  and  the  resulting  prints 
are  no  better  than  blue  prints  for  ordinary  use.  White  prints  are 
used  principally  when  it  is  desired  to  call  attention  to  drawings  of 
unusual  importance.  Drawings  which  are  continuously  used  in  the 
shop  may  be  mounted  on  stiff  cardboard  and  varnished.  These  will 
not  soil  so  quickly  and  dust  and  oil  may  be  removed  with  a  cloth. 
There  will  usually  be  from  twelve  to  fifteen  sets  of  prints  required, 


468  MILL  BUILDINGS 

distributed  as  follows:     Six  for  the  shops,  one  for  the  inspector, 
two  for  approval,  and  two  or  three  sets  for  the  owners'  files. 


Fig.  651. 

PHOTO  REPRODUCTION. 

There  has  been  but  little  progress  in  the  methods  of  copying 
drawings  since  the  advent  of  blue  printing.  Photographic  repro- 
duction is  occasional!}'  used,  but  not  as  extensively  as  its  merits 
deserve.  The  reason  this  method  is  not  more  generally  used  is  no 
doubt  its  extra  cost,  but  this  is  small  when  compared  to  the  total 
cost  and  benefit  gained  by  smaller  sheets,  especially  for  field  use. 
Large  sheets  are  awkward  to  handle  am^where,  but  during  erection 
it  is  often  impossible  to  open  large  drawings  unless  on  a  table  or 
under  the  protection  of  a  shed  or  office.  Small  size  drawings,  8  by 
10  inches,  or  even  twice  as  large,  can  be  conveniently  handled,  but 
standard  size  sheets,  24  by  36,  can  be  consulted  only  where  a  table 
is  available.  The  cost  of  photographic  reproduction  is  from  15  to 
20  per  cent  more  than  the  cost  of  blue  printing,  but  this  is  hardly  a 
consideration  when  compared  to  its  advantages.  Drawings  of  stand- 
ard size  can  easily  be  reduced  to  8  by  12  inches  by  the  photographic 
process,  when  the  lines  are  heavy  and  carefully  made.  On  a  build- 
ing contract  amounting  to  $200,000  the  extra  cost  of  photo  repro- 
duction of  drawings  would  not  exceed  about  $300. 


CHAPTER  XLVI. 

COST  OF  STEUCTUEAL  WOEK  SHOP-DEAWINGS. 

There  are  two  methods  of  estimating  the  cost  of  shop  drawings 
for  structural  steel  work,  one  of  which  is  a  valuable  check  on  the 
other.  The  first  is  to  estimate  carefully  the  probable  number  of 
sheets  that  will  be  needed  and  to  multiply  this  number  by  the  cost 
per  sheet,  and  the  other  method  is  to  estimate  by  the  usual  cost  of 
drawings  per  ton  of  steel  work.  The  former  method  is  the  better 
one. 

Ordinary  structural  work  shop  drawings,  24  by  36  inches  in  size, 
cost  on  an  average  $14  to  $15  per  sheet,  including  making,  check- 
ing and  correcting  the  drawings,  checking  estimates  and  stress 
sheets,  designing  details,  machine  work  or  mechanical  appliances, 
and  ordering  material.  This  cost  does  not  include  making  general 
designs,  stress  sheets  or  estimates,  which  is  done  in  the  estimating 
department.  Multiplying  the  total  number  of  needed  drawings 
by  $15,  will  therefore  give  the  total  estimated  cost.  In  using  this 
method,  the  number  of  sheets  must  be  carefully  counted  in  liberal 
numbers,  for  extra  ones  are  often  needed.  Drawings  made  by 
experienced  and  better  paid  men  may  cost  as  low  as  $8  to  $10  per 
sheet,  while  those  made  by  lower  priced  and  less  experienced  men 
or  beginners  may  cost  twice  as  much.  A  drawing  that  is  carefully 
laid  out  at  the  beginning  and  completed  by  a  competent  workman, 
needs  very  little  checking  and  will  be  more  quickly  made.  It  would 
seem,  therefore,  that  an  office  should  have  no  beginners,  but  it  is 
necessary  to  have  men  in  training  to  replace  others  who  may  leave. 

The  second  method  of  estimating  the  cost  of  drawings  is  to 
figure  them  at  a  certain  price  per  ton  of  steel  work,  which  is 
obtained  from  actual  office  records  for  buildings  of  various  kinds. 
These  prices  are  as  follows : 

TABLE  LXX1. 

COST  OF  SHOP  DRAWINGS. 

Per  ton. 

Steel  cage  office  buildings,  entire  steel  frame $1.50 

Steel  cage  office  buildings,  interior  steel  frame  only 1.25 


*H.  G.  Tyrrell,  Iron  Age,  July  11,  1901. 

469 


470  MILL  BUILDINGS 

Steel  cage  office  buildings,  interior  steel  frame,  cast  iron  cols 70 

Steel  cage  office  buildings,  floor  framing  only 85 

Roof  trusses  only,  on  walls 1.25 

Eoof  trusses  and  columns 2.50 

Entire  mill  buildings 2.60 

Bins  and  hoppers .  . 2.50 

Tipples,  mining  head- frames $4.00  to  6.00 

Hip  and  valley  roofs,  for  fine  residences  or  monumental  bldgs,  $6.00  to  8.00 

By  this  method  the  total  cost  of  drawings  may  be  estimated  by 
multiplying  the  estimated  number  of  tons  of  steel  work  by  the  cost 
per  ton,  as  given  in  the  above  table. 

Detail  shop  drawings  will  cost  less  when  general  details  have 
previously  been  made  by  another  engineer,  but  if  engineers'  plans 
have  no  dimensions,  and  these  must  be  found  from  general  and 
architectural  drawings,  there  is  then  little  or  no  saving  from  them. 

Detail  drawings  made  by  working  from  an  architect's  general 
plans  without  a  structural  engineer's  steel  plans,  will  cost  about 
30  per  cent  more  than  given  in  the  table  above. 

The  making  of  drawings  is  70  per  cent  of  the  total  cost,  check- 
ing and  correcting  them,  18  per  cent,  and  general  office  expense, 
including  service  of  head  draftsman,  rent,  light,  heat,  stationery, 
insurance  and  janitor  service,  12  per  cent. 

Generally  speaking,  experienced  draftsmen  should  make  from 
30  to  40  square  feet  of  finished  drawings  per  week,  including 
making  corrections  after  they  are  checked,  while  a  beginner  may 
not  make  over  half  that  amount.  Drawings  for  ordinary  mill  build- 
ings, including  the  design  of  details,  order  bills  and  shop  lists,  cost 
not  more  than  $1  per  square  foot. 

The  above  costs  are  taken  from  the  author's  private  records  in 
a  drafting  office  employing  forty  men,  with  a  squad  system,  and 
covering  a  period  of  40  weeks,  in  which  time  1,693  drawings  were 
made  for  515  different  contracts.  The  wages  paid  were  as  follows : 

1  Head  draftsman,  $180  per  month $180 

5  Squad  foremen,  $125  per  month 625 

2  Checkers,  $125  per  month 250 

3  Checkers,  $100  per  month 300 

3  Draftsmen,  $100  per  month 300 

2  Draftsmen,  $90  per  month 180 

3  Draftsmen,  $80  per  month 240 

6  Draftsmen,  $75  per  month 450 

6  Draftsmen,  $60  per  month 360 

6  Draftsmen,  $50  per  month 300 

1  Draftsman,  $40  per  month 40 

Total  per  month $3,225 

The  actual  amount  of  money  paid  in  40  weeks  for  1,693  shop 


COST  OF  STEUCTUEAL   WOEK  SHOP-DEAW1NGS  471 

drawings  after  deducting  time  that  men  were  absent  on  vacations, 
amounted  to : 

Making  drawings $16,465  or     70%  of  total 

Checking   drawings 4,390  or     18%  of  total 

General  expense 2,960  or     12%  of  total 

$23,815  or  100%  of  total 

In  addition  to  the  above,  114  sheets  of  standard  office  drawings,  8 
by  13  inches,  were  made,  costing  $1,100. 

The  1,693  standard  sheets  of  shop  drawings,  24  by  36  inches  in 
size,  with  a  total  cost  of  $23,815,  had  therefore  an  average  cost  of 
$14  per  sheet.  The  item  of  general  expense  includes  the  wages  of 
head  draftsman,  office  boy,  cloth,  paper,  stationery,  heat,  light,  rent, 
insurance  and  janitor  service. 


CHAPTER  XL VII. 

DIRECTIONS  FOR  EXPORTING  STEEL  BUILDINGS. 

America's  export  business  is  an  important  part  of  its  entire 
trade.  This  business  grew  to  large  proportions  in  the  decade  pre- 
ceding 1900  and  it  is  still  increasing.  Steel  bridges  and  buildings 
have  been  exported  to  Japan,  China,  Egypt,  India,  South  America 
and  various  islands  of  the  ocean,  and  the  entire  commercial  world 
will  probably  soon  look  to  America  to  supply  much  of  its  manufac- 
tured goods.  American  export  business  was  slow  in  starting,  but 
when  foreign  countries  discovered  the  attractive  prices  and  deliv- 
eries that  were  made,  the  continuance  of  the  trade  was  assured. 
One  of  the  reasons  for  the  delay  was  the  absence  of  price  lists  in 
American  catalogues.  A  few  enterprising  companies  have  for  sev- 
eral years  issued  attractive  albums  showing  special  buildings  made 
by  them,  but  none  of  them,  prior  to  1900,  issued  standard  designs 
with  advertised  prices  and  discounts  from  which  foreign  buyers 
could  select  or  order  without  delay.  Price  lists  of  this  kind  have 
long  been  issued  by  European  firms,  and  buyers  in  foreign  countries 
found  it  more  convenient  to  order  from  them,  rather  than  wait  sev- 
eral months  in  getting  American  quotations  by  mail.  Two  or 
three  months'  time  would  easily  be  consumed  in  correspondence,  and 
cable  messages  costing  from  30  to  80  cents  per  word  were  too 
expensive. 

Among  common  forms  of  buildings  exported  to  other  countries 
may  be  mentioned  sugar  houses,  rice  mills,  warehouses,  railroad 
stations,  saw  mills,  barracks,  hospitals,  hay  shelters  and  dwellings. 
There  is  also  a  large  amount  of  structural  work  in  monumental 
buildings.  The  palace  of  the  Emperor  of  Japan,  recently  built, 
which  was  made  proof  against  fire  and  earthquake,  contained  a  large 
amount  of  American  steel. 

EUEOPEAN  AND  AMERICAN  PRACTICE  COMPARED. 
It  is  surprising  that  Europe  so  long  monopolized  the  world's 
export  trade  in  steel  buildings,  for  European  designs  are  not  usually 
as  economical  as  those  made  in  America.     Some  expensive  features 

472 


EXPORTING  STEEL  BUILDINGS  473 

ordinarily  found  in  building  designs  from  European  shops  will  be 
mentioned. 

It  is  customary  to  find  queen  trusses  or  other  forms  used  with 
long  members  in  compression,  rather  than  in  tension,  and  this  adds 
greatly  to  the  weight.  The  bottom  chords  are  frequently  raised 
at  the  center  two  or  three  feet  above  the  ends,  either  for  better 
appearance  or  for  extra  head  room,  and  this  adds  to  the  chord 
stresses  and  corresponding  sections.  The  web  members  are  short- 
ened, but  the  saving  in  the  web  does  not  equal  the  extra  weight  in 
the  chords,  and  it  is  doubtful  if  the  practice  gives  any  more  pleas- 
ing appearance  than  horizontal  chords,  while  it  has  the  disadvantage 
of  requiring  the  bottom  lateral  plates  to  be  bent,  thus  adding 
expense.  The  European  method  of  making  the  roof  curved  on 
top,  instead  of  a  straight  pitched  roof,  is  also  more  expensive. 

Large  roofs  are  often  erected  at  the  works  where  they  are  made, 
to  see  that  the  parts  will  go  correctly  together.  American  shops 
take  no  such  expensive  precautions,  for  their  methods  are  accurate 
enough  without  it,  as  shop  and  drafting  office  work  in  harmony 
from  drawings  that  have  been  carefully  verified. 

Many  of  their  details  are  also  more  expensive  than  in  America. 
It  is  common  in  European  designs  to  find  such  details  as  clevises, 
pins,  forkeyes,  gibs  and  cotters,  etc.,  instead  of  cheaper  bolted 
joints.  Special  cast  iron  joint  blocks,  truss  shoes,  gutter  heads, 
etc.,  are  common  features,  and  while  the  cast  iron  is  not  expensive 
in  itself,  the  use  of  special  patterns  will  make  the  cost  excessive, 
unless  there  are  a  large  number  of  pieces  of  the  same  kind.  The 
practice  of  using  heavy  T  irons  for  rafters  is  common  in  Europe, 
but  the  cost  of  cutting  T  irons  and  making  connections  to  them  is 
higher  than  the  cost  of  double  angles  which  are  more  easily  sheared, 
and  gusset  plates  between  the  angles  make  symmetrical  joints.  The 
European  practice  of  using  truss  pins  for  connections  instead  of 
bolts  and  rivets  is  an  expensive  one,  its  only  merit  being  tlie 
greater  ease  of  erection. 

SUITABILITY  OF  STEEL  BUILDINGS  FOE  EXPORT. 

A  large  proportion  of  the  steel  buildings  exported  from  Amer- 
ica are  sent  to  warm  countries.  The  reason  for  this  is  evident, 
because  buildings  for  warmer  climates  need  no  heating,  and  wall 
and  roof  covering  of  corrugated  iron  is  sufficient. 

Business  is  more  secure  when  carried  on  in  fireproof  buildings 
than  when  exposed  to  fire  risk.  Steel  buildings  need  no  insurance, 
but  the  saving  by  their  use  is  not  for  insurance  alone.  The  money 
received  by  a  manufacturing  company  for  a  fire  loss  rarely,  if  ever, 


474  MILL  BUILDINGS 

repays  them  for  the  real  loss  incurred,  for  the  stoppage  of  business 
and  the  delay  in  finishing  contracts  are  frequently  more  serious 
than  the  fire  itself  and  cannot  be  covered  by  insurance.  Buildings 
for  heavy  manufacturing  require  the  service  of  shop  cranes,  which 
are  an  economic  necessity  to  meet  competition.  The  supports  and 
framing  of  these  cranes  should  be  made  of  steel,  for  heavy  joints 
in  wood  are  difficult  to  make  and  are  apt  to  work  loose,  thus  causing 
the  traveling  cranes  to  bind  on  the  tracks. 

Steel  buildings  are  preferred  in  foreign  countries  as  well  as  at 
home,  because  the  cost  of  repairs  and  insurance  on  wooden  build- 
ings will  more  than  pay  the  interest  on  extra  money  spent  for 
permanent  ones. 

DESIGN  OF  EXPOET  BUILDINGS. 

Buildings  for  export  to  tropical  or  semi-tropical  countries  usually 
contain  features  not  found  on  similar  ones  in  the  United  States. 
As  they  require  no  heating,  corrugated  iron  covering  for  wall  and 
roof  are  suitable  for  buildings  of  low  or  medium  cost,  but  they 
must  be  well  ventilated,  for  if  not,  the  direct  rays  of  the  sun  on 
the  metal  makes  the  interior  excessively  hot.  Buildings  for  cold 
countries  where  artificial  heating  in  winter  is  needed,  must  have 
non-conducting  walls.  The  buildings  must  in  any  case  be  weather- 
proof, strong,  with  good  light  and  ventilation,  and  the  location  of 
columns  and  other  parts  of  framing  studied,  so  there  will  be  no 
interference  with  machinery  or  other  contents.  The  cooling  and 
ventilating  of  buildings  in  warm  climates  is  quite  as  important  as 
heating  them  in  colder  regions.  It  is  therefore  the  practice  of  the 
writer  to  provide  large  ventilation  area  in  the  roof,  and  to  use 
swinging  side  shutters  with  continuous  open  ventilation  from  one 
to  two  feet  in  width,  beneath  the  eaves.  These  openings  should  be 
covered  with  a  heavy  grade  of  galvanized  wire  with  J-inch  mesh, 
which  will  admit  a  continuous  current  of  air  but  exclude  animals, 
birds  and  insects.  Another  feature  suitable  for  iron  buildings  in 
warm  countries  is  the  wide,  overhanging  eave,  to  protect  the  sides 
of  the  building  from  the  sun.  These  eave  projections  may  vary  from 
4  to  8  feet,  depending  upon  the  height  of  side  walls.  Figs.  33  and 
34  show  market  buildings  designed  in  this  way,  and  the  wide  eaves 
not  only  protect  the  sides  of  the  building  from  the  sun,  but  serve 
also  as  a  shelter  above  the  sidewalks  where  people  congregate  around 
market  stalls.  The  overhanging  eave  is  indispensable  for  dwell- 
ings, for  the  metal  covering  exposed  to  the  sun  would  be  intoler- 
ably warm  were  it  not  for  the  sunshade  verandas  and  free  air  circu- 
lation between  the  upper  ceiling  and  the  roof. 


EXPORTING  STEEL  BUILDINGS  475 

Another  method  of  preventing  building  interiors  from  becoming 
excessively  warm  in  tropical  countries  is  to  line  the  walls  with  some 
kind  of  non-conductor,  such  as  asbestos  board.  When  put  up  with 
tight  joints,  this  lining  will  prevent  heat  radiating  in  the  building 
and  at  the  same  time  does  not  add  inflammable  material  or  expose 
the  building  to  risk  from  fire. 

Thatched  roofs  produce  a  cooler  interior  than  those  covered 
with  corrugated  iron,  and  thatch  matting  is,  therefore,  often  pre- 
ferred. Heat  will  not  penetrate  through  the  thatch  and  radiate 


Fig.  652. 

from  the  under  side  as  it  will  with  iron.  This  kind  of  roof  is 
popular  for  small  dwellings  in  the  hot  region  of  southern  Cali- 
fornia, as  shown  in  Fig.  652. 

The  suitability  of  other  native  building  material  should  also  be 
considered.  In  some  southern  countries,  walls  made  of  stucco  or 
plaster  are  less  expensive  than  metal  sheathing,  as  local  products 
can  be  secured  at  small  expense  and  workmen  are  accustomed  to 
using  it.  A  market  building  with  stucco  walls  is  shown  in  Fig.  32. 

Buildings  must  be  so  designed  that  their  parts  can  be  conven- 
iently stored  on  shipboard  and  easily  erected  by  labor  in  the  foreign 
country. 

The  cost  of  those  erected  in  other  lands  is  greater  than  in 
America,  owing  to  the  extra  ocean  freight  or  other  transportation 
and  the  additional  handling  caused  thereby.  It  is  therefore 
economical  when  using  corrugated  iron  for  walls  and  roof,  to  have 
all  such  metal  galvanized.  The  extra  expense  of  the  galvanizing 
will  be  small  in  comparison  to  the  total  expense  and  the  benefit 
obtained  by  the  use  of  non-rusting  sheathing.  An  asbestos  covered 
metal  described  on  page  284  is  also  suitable  for  export  buildings. 


476  MILL  BUILDINGS 

SUGGESTIONS  FOR  FOREIGN  PURCHASERS. 
Foreign  buyers  find  it  to  their  advantage  in  asking  for  prices 
on  steel  buildings  to  make  only  such  requirements  and  specifica- 
tions as  are  absolutely  essential  for  their  needs.  It  is  economical 
to  leave  details  to  the  builders,  for  shops  can  manufacture  cheaper 
when  following  their  own  methods  than  in  filling  special  require- 
ments of  the  buyers  which  may  not  be  important.  It  is  generally 
cheaper,  therefore,  for  the  buyer  to  permit  American  shops  to  fur- 
nish their  own  plans  rather  than  to  manufacture  from  plans  sub- 
mitted. Many  details,  such  as  doors,  windows,  ventilator  shutters, 
louvres,  etc.,  are  as  effective  in  one  style  as  in  another,  and  can 
be  made  by  manufacturers  according  to  their  own  practice  at  a 
much  less  cost  than  if  required  to  follow  a  special  plan.  The 
buyer  should,  therefore,  state  only  essentials  which  must  be  fol- 
lowed, special  floors,  loading,  location  of  machines,  etc.  The 
ground  floor  and  foundations  should  be  supplied  by  local  builders, 
unless  they  contain  steel  framing,  as  those  who  are  on  the  ground 
and  familiar  with  local  conditions  can  do  the  work  cheaper  than 
others  at  a  distance. 

SUGGESTIONS  FOR  EXPORTERS. 

The  total  cost  of  a  building  to  a  purchaser  in  a  foreign  country 
is  divided  into  five  items,  as  follows: 

(1)  Cost  of  all  material  on  board  cars  at  the  manufacturer's  shops. 

(2)  Railroad  freight  from  the  manufacturer's  shops  to  seaport  and  deliver- 

ing same  on  wharf  beside  the  vessel. 

(3)  Cost  of  ocean  freight,  including  loading  the  material  into  the  vessel 

and  unloading  it  again  at  its  destination. 

(4)  Cost  of  freight  or  hauling  in  the  foreign  country. 

(5)  Cost  of  erection  at  the  site. 

Quotations  on  steel  buildings  for  export  are  made  by  American 
manufacturers  in  either  of  two  ways:  (1)  on  the  material,  de- 
livered beside  the  vessel  at  seaboard,  together  with  the  weight,  num- 
ber of  pieces  and  cubic  contents  of  the  shipment;  (2)  price  deliv- 
ered complete  to  the  purchaser  at  the  site,  including  freight  and 
ocean  charge. 

There  are  several  companies  in  New  York  which  devote  their 
attention  to  export  business,  including  not  only  steel  buildings, 
but  various  other  American  products,  such  as  machinery,  track 
material,  etc.,  and  these  companies  get  prices  from  American  shops 
and  buy  their  supplies  from  the  lowest  bidders.  They  are  well  in- 
formed in  reference  to  ocean  freight  rates  and  transportation 
charges  in  foreign  countries,  and  are  able  to  make  quotations  on  the 
material  delivered  in  other  countries  at  the  site.  These  companies 


EXPORTING  STEEL  BUILDINGS  477 

have  arrangements  whereby  their  correspondence  is  carried  on  in 
the  language  of  the  purchaser,  and  this  feature  is  an  advantage  to 
them  in  securing  business.  The  buyers  may  be  unable  to  corre- 
spond in  English  and  may  not  understand  quotations  in  dollars 
and  cents,  and  it  may  be  very  attractive  to  them  to  receive  letters 
and  prices  in  their  own  language. 

Other  companies  which  are  not  prepared  to  carry  on  corre- 
spondence in  foreign  languages  and  are  not  familiar  with  ocean 
or  foreign  freight  charges,  prefer  to  make  quotations  on  material 
delivered  on  the  wharf  at  American  seaboard,  giving  the  necessary 
data  in  reference  to  space  required,  number  of  pieces  and  tonnage, 
so  freight  charges  can  be  computed.  The  latter  method  has  several 
advantages.  The  purchaser  may  secure  as  low  freight  quotations 
as  the  exporting  company,  and  by  ordering  the  freight  himself 
would  save  the  profit  of  the  middleman.  Another  benefit  from 
making  quotations  at  seaboard  only,  is  that  the  risk  in  connection 
with  ocean  and  foreign  freights  is  not  assumed  by  the  American 
manufacturer,  for  if  he  includes  these  freights  in  his  prices,  he 
will  add  a  percentage  for  the  risk  incurred.  The  purchaser  may 
save  this  charge  by  assuming  the  freight  risk  himself. 

Ocean  freight  charges  depend  upon  three  factors,  (1)  the  weight 
of  the  shipment,  (2)  the  number  of  pieces  that  must  be  handled, 
(3)  the  cubic  contents  which  the  material  will  occupy  in  the  ship. 
It  is  necessary,  therefore,  in  giving  prices  at  seaboard,  to  furnish 
the  buyer  with  weight,  number  of  pieces  and  cubic  contents,  in 
order  that  he  may  obtain  the  freight  charges. 

The  shipping  weight  is  ascertained  in  the  usual  way  by  weigh- 
ing the  cars  after  they  are  loaded. 

The  number  of  pieces  should  be  a  minimum,  for  the  charges 
increase  with  the  number.  It  is  economical  to  fasten  small  pieces 
together  in  bundles  of  as  large  size  as  can  be  conveniently  handled, 
uniting  them  with  wire  through  the  rivet  holes  to  avoid  their  falling 
out.  Rivets,  bolts,  washers  and  other  small  parts  must  be  shipped 
in  kegs  or  boxes,  keeping  different  sizes  and  lengths  separate,  and 
each  box  must  be  plainly  marked.  Bags  for  nails,  spikes  or  bolts 
are  unsatisfactory,  for  they  tear  and  expose  the  contents  to  the 
water,  causing  them  to  rust.  Corrugated  iron  must  be  shipped  in 
bundles  tied  together  with  wire,  all  the  various  lengths  and  thick- 
nesses being  bundled  by  themselves,  and  the  gage  and  length 
marked  on  each.  Glass  or  other  fragile  articles  must  be  packed  in 
excelsior  or  straw,  and  carefully  boxed.  Ocean  freight  receives 
rough  handling,  and  shippers  must  use  great  care  that  no  pieces 


478  MILL  BUILDINGS 

are  injured.  Eecords  from  American  ports  show  that  the  most 
carefully  packed  and  crated  export  shipments  come  from  manufac- 
turers of  agricultural  implements,  and  others  should  use  the  same 
care.  The  shipper  should  be  liberal  in  estimating  the  number  of 
pieces,  as  the  estimated  number  is  often  exceeded. 

The  cubic  contents  of  a  shipment  is  computed  by  estimating 
the  space  occupied  by  the  riveted  sections  when  piled  together  to 
the  best  advantage.  The  maximum  dimensions  for  single  cars  are 
widths  up  to  8  feet,  heights  of  10  feet  and  lengths  30  to  40  feet. 
Riveted  sections  may  be  piled  above  each  other  on  the  cars  to  a 
height  of  10  feet.  Small  parts,  such  as  kegs,  boxes,  separate  gusset 
plates  and  the  like,  can  be  placed  in  the  open  spaces  between  the 
riveted  sections,  and  it  is  necessary  to  measure  only  the  space  occu- 
pied by  the  larger  pieces.  In  piling  riveted  sections  upon  each 
other,  strips  of  wood  or  pieces  of  plank  must  be  inserted  between 
the  steel  sections  to  prevent  their  damaging  each  other,  and  in 
measuring  the  cubic  contents  on  the  cars,  allowance  must  be  made 
for  these  packing  strips.  The  cubic  contents  of  the  various  car 
loads  may  then  be  measured,  and  their  sum  will  be  the  space  re- 
quired in  the  vessel. 

The  shipper  should  inquire  as  to  the  maximum  size  and  length 
of  pieces  that  the  vessel  will  accept,  or  that  can  be  loaded  through 
the  hatchways.  Some  ships  will  not  take  material  longer  than  40 
feet  and  greater  lengths  require  splicing. 

MAEKING  PIECES. 

The  manufacturer  must  furnish  the  purchaser  with  erection 
drawings  so  clearly  made  and  plainly  marked  that  the  building 
can  be  easily  erected  by  unskilled  labor.  The  manufacturer  may  be 
obliged  to  send  an  experienced  foreman  to  superintend  the  erection 
of  large  orders,  but  small  shipments  will  not  require  this  expense. 
The  erection  drawings  should  show  the  mark  of  every  piece,  the 
size  and  length  of  field  bolts  or  rivets,  position  of  washers,  splice 
plates,  etc.  Erection  drawings  for  export  buildings  must  be  made 
so  clear  that  ordinary  mechanics  can  understand  them.  It  may 
occasionally  be  necessary  to  mark  the  erection  plans  in  both  feet 
and  meters,  so  either  system  of  notation  can  be  used,  but  there  will 
seldom  be  need  for  other  than  the  English  language  on  the  draw- 
ings, for  in  nearly  all  countries  English  speaking  foremen  can  be 
employed.  Where  there  is  doubt  in  reference  to  the  language;  the 
drawings  can  first  be  worded  in  English  and  the  corresponding 
wording  of  the  foreign  country  added. 


EXPORTING  STEEL  BUILDINGS  479 

Marking  should  be  the  same  as  for  domestic  work,  and  when  a 
number  of  pieces  of  the  same  mark  are  shipped  in  bundles,  that  of 
the  separate  pieces  will  then  be  the  shipping  mark  of  the  whole 
crate.  Each  piece,  box,  bundle  or  keg  must  have  its  own  individual 
shipping  mark. 

When  steel  buildings  are  consigned  to  districts  in  foreign  coun- 
tries which  are  not  accessible  by  rail  or  regular  highways,  material 
for  the  buildings  is  sometimes  transported  on  mules,  and  the  sepa- 
rate pieces  must  then  not  exceed  about  8  feet  in  length  nor  250 
pounds  in  weight.  Each  animal  is  loaded  with  two  equal  pieces, 
the  combined  weight  of  which  must  not  exceed  500  pounds.  This 
method  of  transportation  is  used  for  conveying  material  to  mining 
districts  in  mountain  regions  before  railroads  or  highways  have 
been  built.  Roof  purlins  may  be  shipped  in  8  foot  lengths  by  mak- 
ing them  continuous  over  the  trusses  and  splicing  approximately 
at  the  points  of  contra  flexure.  A  set  of  buildings  of  this  kind  was 
designed  by  the  writer  for  export  to  a  mining  camp  in  the  Andes 
mountains. 

DIRECTIONS  TO  FOREIGN  PURCHASERS  IN  COMPARING  PLANS. 

In  comparing  various  designs  that  he  has  received  for  a  mill 
building,  the  purchaser  should  carefully  note  what  items  are  in- 
cluded in  the  bids.  Some  manufacturers,  in  order  to  make  their 
prices  low,  show  the  building  complete  in  all  its  parts  on  the  draw- 
ing, but  their  prices  include  only  the  steel  structural  work  and 
metal  sheathing,  charging  extra  for  miscellaneous  items  such  as 
doors,  windows,  shutters,  etc.  Corrugated  iron  must  be  compared 
by  weight  rather  than  by  gage,  as  there  are  several  metal  gages, 
and  confusion  might  occur. 

A  design  with  excessive  strength  in  some  parts,  but  lacking  in 
others,  is  very  little  better  than  one  which  is  lacking  in  strength 
throughout.  Weight  added  where  not  needed  is  a  detriment,  for 
the  buyer  must  pay  freight  on  the  useless  weight.  In  comparing 
competitive  plans,  the  purchaser  may  find  that  some  drawings  are 
made  to  an  exaggerated  scale,  various  parts  and  members  being 
shown  heavy  with  neither  size  nor  weights  marked  thereon.  This 
effort  to  give  a  design  the  appearance  of  strength  on  the  drawing  is 
deceptive  and  misleading,  and  the  merit  of  the  building  must  not 
be  judged. by  the  appearance  of  an  elaborate  drawing  made  to  an 
exaggerated  scale  with  sizes  omitted.  Many  manufacturers  who 
would  not  dare  to  erect  a  bridge  of  doubtful  strength  are  willing 
to  design  and  put  up  buildings  which  are  stressed  under  maximum 


480  MILL  BUILDINGS 

loads  up  to  or  beyond  their  elastic  limit,  the  chief  requirement 
being  that  they  are  well  braced.  The  loads  on  buildings  which  have 
no  traveling  cranes  are  mostly  static,  and  maximum  wind  loads 
occur  very  seldom.  Manufacturers  therefore  often  specify  sizes 
for  export  buildings  which  are  dangerously  weak,  knowing  that  the 
buyers  are  far  away,  and  even  if  the  work  is  unsatisfactory,  there 
will  be  little  probability  of  complaint. 

Steel  frames,  such  as  those  used  for  the  temporary  buildings 
for  various  expositions,  are  ordinarily  proportioned  with  high  unit 
stresses  from  20,000  to  25,000  pounds  per  square  inch.  The  expe- 
dient for  temporary  buildings  is  permissible,  but  cannot  be  sanc- 
tioned for  permanent  ones.  Unfortunately,  however,  too  many 
buildings  supposed  to  be  permanent,  are  no  better  than  others 
which  are  known  to  be  temporary. 

It  is  the  practice  of  some  structural  shops,  after  securing  a 
building  contract,  to  put  designs  and  plans  through  what  they  call 
the  "reduction  process/'  The  plans  are  again  submitted  to  the 
designer  or  to  some  engineer,  whose  duty  it  is  to  revise  them  and 
cut  out  weight  or  expense  any  place  that  safety  will  allow.  Every 
pound  is  omitted  that  is  not  absolutely  required  to  make  the  building 
stand  until  erected  and  paid  for.  Pieces  must,  of  course,  have  suffi- 
cient strength  to  prevent  their  bending  or  breaking  during  shipping 
and  erection.  Between  this  method  of  making  extremely  light  de- 
signs, and  the  European  method  of  making  excessively  heavy  ones, 
there  is  a  mean  where  the  building  is  strong  enough  for  its  maxi- 
mum loads,  and  yet  not  wasteful.  Generally  speaking,  designs  sub- 
mitted by  European  firms  for  steel  mill  buildings  in  foreign  coun- 
tries are  from  20  to  25  per  cent  more  expensive  than  designs  from 
shops  in  the  United  States.  This  percentage  is  approximate  only, 
and  taken  from  the  writer's  records  when  bidding  on  this  class  of 
work. 


INDEX 


PAGE 

Accuracy  in  Drawing,  Need  of.  446 
Adhesion  of  Concrete  to  Metal.  168 
Advertising  Not  Intended..  .Preface 

Africa,  Buildings   for 45 

Air  Space  in  Eoof 243 

Air,  Amount  Required 89 

American  Bridge  Co.  Office 433 

American  System  of  Reinforcing  246 

Anchor  Bolts,  Efficiency  of 201 

Locating  of   203 

Plates    202 

Test  of   202 

Table  of   201 

Anchors  for  Machines 221 

Foundation    201 

Weight   of    414 

Anchorages  on  Walls 215 

Anti-Condensation   Roof   Lining 

69,    285 

Architectural  Drawings    250 

Architectural  Design,  Secondary  12 
Area  on  Soil  for  Foundations.  .  198 
Armories  Without  Columns.  .  . .  151 

Arrangement  of  Buildings 2 

Artistic  Arrangement  of  Plants  3,  4 
Asbestos  Covered  Corrugated 

Iron     284 

Corrugated  Sheathing  • 262 

Paper  Lining  for  Corrugated 

Iron    285 

Roofing    269 

Asphalt,  Composition  of 225 

Floors    217,  225 

Paint     384 

Roofing     267 

Assembly    Marks 463 

Bakery,    Cost    of 58 

Beams,  Cost  of  Mill  Work  on.  422 

Classification  of 413 

Excess  Length  to  Order....  456 

Spacing  in  Floors. 406 

Bearing  Power  of   Soils 196 

Bethlehem    Shapes 422 

Blank    Office    Forms 405,463 

Blue   Print    Room 435 

Blue    Printing 467 

Blue  Prints,  Changes  on 465 

Book    Tile 250 

Borders  on  Drawings 460 

Bottom  Chords 130 


PAGE 

Box   Gutters 303 

Box    Skylights 318,  327 

Bracing  of  Buildings.  .19,  150,  153 

Brick   Floors 219,  224 

Piers   198 

Standard  Size  of 205 

Cost  of   205 

Weight  of   108 

Walls 205 

Brickwork,    Cost    of 206',  428 

Bridges,   Factory  Foot 374 

Building   Frames, 

Outline    of 120,121,122,  123 

Building  Laws 69 

Building  Material,  Presence  of  10 

Business    Blocks 407 

Calculations  Preface 

Cambering  Bottom  Chords.164,  473 

Cambering  Trusses 459 

Capital  Invested  in  Plants.  ...  20 
Car  Barns, 

Provision  Against  Fire....  22 

Car  Shed  Doors 372 

Carbonizing  Coating 385 

Carey's  Roofing 269 

Carpentry  Work,  Cost  of 428 

Casings,  Door  and  Window...  298 

Catalogue  Cases 440 

Ceilings,  Color  in  Office 442 

When  Permitted 159 

Cement  Coating 385 

Changes  on  Drawings, 

How  Made 463 

Charts  for  Weight 

of  Roofs 97,  98,  99,  100,  101 

Character  of  Buildings 20 

Check  Lists  414 

Checking  Estimates 403 

Checking  Drawings 448,  464 

Checkers,  Duties  of 464 

Chief  Engineer 450 

Chimney  Flashing 297 

Cinder  Concrete  Roof 245 

Cinders  in  Ground  Floor 223 

City  or  Suburban  Plants 8 

City  Property,  Value  of 7,  8 

Classification  of  Estimate....  416 
Cleaning  Metal 398 

By  Sand  Blast 391,  392 

Inside   of  Buildings 14 


481 


482 


INDEX 


PAGE 

By   Pickling 390 

Clevis    Forms 463 

Clevises    152 

Clinch   Nails,   Size   of 28] 

Clothes   Presses 19 

Coal    Pockets, 

Weight   of  Steel  in 412 

Coal   Storage   Sheds 156 

Coal  Tar  Paint 384 

Cold  Climates,  Eoofs  for 243 

Cold    Water   Paint 387 

Column  Bases,  Table  of 148 

Weight  of 412 

Column  Brackets  for 

Crane   Girders    147 

Columns,   Buildings 

without  any  inside 151 

Circular  Covering  for 148 

Concrete     173 

Details  of 142 

Forms    143,  146 

H    Shape 424 

in  Brickwork 146 

in  End  of  Buildings 146 

in   Masonry   Walls,   not 

economical 21 

in  Walls 34 

Number    of 142 

Outline   for   Crane   Girder...  148 

Placing  of  to  suit  Machines.  13 

Reinforcement   for 171 

Eeinforced,   Hooped    or 

Wound    174 

Spacing  in  Tall  Buildings..  405 
Spacing  for  North  Light 

Eoofs    182 

Timber  preferable  to   Cast 

Iron 16'3 

Vent  Holes  in  Wooden.....  165 

Web,  Plate  or  Lattice 143 

Combination    Roof    Gutters...  304 

Commercial  Panics,  Effect  of.'.  8 

Comparing  Designs 479 

Comparative    Cost    of 

Buildings    58,  62 

Composition    Eoofing 266 

Computations,  Time  Wasted  in  404 

Concrete  Block  Walls 210 

Blocks,  Kinds  of 210 

Column  Footings,  Forms  for.  198 

Columns   173 

Cost  of 176 

Frames    for   Build- 
ings     175,177,  178 

Framing 168 

Floors  and  Eoof 172 

Floors,    Cost   of 221 

Girders,   Cost   of 173 

Piers    197 

Piles    200 

Eoof  Slabs,  Monolithic 244 


PAGE 

Eoofs    without   Forms 247 

Slabs,    Moulded 209 

Slab    Eoofs t.   244 

Trusses    171,  193 

Walls,   Forms  for 210 

Wall  Slabs,  Use  of 210 

Condensation  on  Eoofs 243 

Walls    37 

North    Light    Eoofs 187 

Prevention    of 69 

Connections,   Detailing.  .  .  .454,  457 

on    Trusses 126 

Connection  Plates, 

Symmetrical    458 

Construction    Details 195 

Contracts,  Numbering  of 451 

Conveying  Appliances 19 

Cooling  of  Buildings 474 

Copenhagen  Foundry,  Cost  of.     40 
Copper  Downspouts,  Cost  of..   307 

Copying    Drawings 460-467 

Lists    466 

Corn  Products  Plant 2 

Corner  Capping 297 

Cornice   and   Gutter 217 

Cornice,  Metal 294 

Correcting   Drawings 465 

Corrugated  Asbestos  Board...    262 

Table    of 263 

Cost  and  Weight  of 264 

Corrugated    Iron 273 

Cost  of  Laying 283 

Doors    363 

Floors   232 

Method  of  Laying 280 

Method    of   Fastening 280 

Method  of  Making 273 

Moment  of  Inertia  of 277 

On  Wood  Studs 281 

Preservation  of 274 

Eequired   Eoof  Pitch  for...    279 

Eoof  of  Curved  Sheets 120 

Safe  Load  on 278 

Section   Modulus 277 

Shipping  of 477 

Size  and  Weight  of 275 

Standard  Weight 276 

Strength  of 277 

Tables  of 276 

Walls,    Cost    of 41 

Weight  and  Cost  of 283 

Cost   Estimates,   Approximate.   418 

Close   418 

Cost   of   Buildings 55,56,     57 

One  or  More  Stories.  .23,  25,     28 

Cost  of  Steel  Buildings 38 

Cranes,    Capacity    of 136 

Clearances   for 14 

Cost  of  Buildings  with 39 

Crane   Girders,  Plate  or 

Lattice   .  .   139 


INDEX 


483 


PAGE 

Loads     114,  115 

Eails    137,  139 

Supports,  Weight  of  Steel  in  411 

Systems 136 

Systems,  Extension  of*  to 

yard    147 

Systems,  Weight  of  Steel  in.  117 

Tables    15,16,17,  18 

Wheels,  Load  on 115 

Crating,  Small  Parts  for 

Shipping    477 

Credits,    Authors Preface 

Cupola    Floors 39 

Curtain  Walls 34 

Curved  Eoof  Forms 473 

Dating  of  Eecords 452 

Design  of  Buildings 405 

Framing 119 

Details  of  Construction 195 

Expensive    European 473 

Development    of    Plants 5 

Dimension  Lines  on  Drawings.   460 
Dining  Room  for  Employees..   433 

Door    Casings    298 

Door  Hinges,  size  of 361 

Door    Tracks 364 

Doors,    Automatic    Closing....   363 

Batten    360 

Car  Shed 372 

Corrugated    Iron 364 

Cost    of 428 

Extra  Large  one,  when 

needed    36 

Frame   for  Corrugated 

Iron    345,  365 

Glass  Panels  in 362 

Horizontal    Folding 365 

Horizontal    Sliding 359 

Number  and  Location  of.  ...   358 

Reinforced   Concrete 358,  367 

Ritter  Folding 366 

Size  of 359 

Side  Swinging   36'2 

Special  Pier  Shed 368 

Swing    Sliding 365 

Tin    Clad 362 

Vertical    Rolling 370 

Wood   Panel 360 

Wooden,  Size  of  Material  in  361 

Weight  of  Metal  Covered.  . .   361 

Dovetail  Sheets,  Safe  Load  on.  250 

Downspouts    299 

Size  and  Cost  of 305,  306 

Drainage    of   Roofs 69,     73 

Drafting   Boards 438 

Drafting    Office 430 

Cost   of 470 

Division  of 448 

Expense  of 445 

Location    of 431 


PAGE 

Organization    of 444 

Practice    454 

Rules 447 

Drafting    Paper 439 

Drafting  Tables 436,  437,  438 

Draftsmen 403 

Capabilities    of 470 

The   Chief 448 

Duties  of 451 

Personal 449 

Drawings,   Architectural 449 

Assembling   of 460 

Correcting  of 465 

Cost  of 469 

Erection  467 

Importance  of  Plain  Ones..   445 

Making  of 445 

Marking  of 463 

Numbering    463 

Show 408 

Size  of 46'0 

Working 445 

Driers  for  Paint,  Acetate  of 

Lead   381 

Litharge 381 

Manganese    381 

Red   Oxide 381 

Zinc   Sulphate 381 

Duplication,  Effect  of,  on  Cost.  164 

Durable    Metal    Coating 384 

Dwellings  for  Employees 52 

Economic  Design,  Theory  of . .       1 

Economy  of  Construction 19 

Electric  Cranes,  Load  From.  . .    115 
Elevators  in  Office,  Location  of  440 

Elevator  Service,  Cost  of 29 

Empirical  Rules  in  Estimating.   410 
Employees,  Relation  to 

Employers   8 

Housing   of 8 

Engineer,   The   Chief 450 

Engineering    Department 402 

Engineering   Magazine, 

Credit  to Preface 

News,    Credit   to Preface 

Record,    Credit    to Preface 

Erecting    Floors 24 

Erection,  Cost  of 424,  469 

Drawings   for  Export 

Work   38,467,  478 

Marks 463 

of  Buildings  at  Works 473 

Errors  on  Drawings 446 

Estimate  Sheets 405,  413,  415 

Estimates,   Analysis   of 409 

Approximate  410 

Classification    of 416 

Numbering    of 404 

Preparation  of  for  Drafting 
Office 426 


484 


INDEX 


PAGE 

Estimating,   Costs 424 

Cost  of   424 

Cost  of  Drawings 469 

Exact    412 

Prices   427 

Quantities    410 

Time  Bequired  in 424 

European  and  American 

Practice  Compared 472 

European  Designs,  Cost  of....  480 

Executive 448 

Expanded  Metal  Walls 208 

Eoof    246 

Stiffened    248 

Expansion  Joint  in  Shop  Walls  216 

Export  Buildings 38 

Design    of 474 

Cost   of 476 

Export  Designs,  Deficient 479 

Exporting     Companies 476 

Exporting,   Maximum  Dimen- 
sions   for 38- 

Steel    Buildings 472 

Exporters,  Suggestions  to 476 

Extension  of  Buildings 19 

Provision   for 146 

Federal  Tile 255 

Ferrolithic  Floor  Plates 233 

Eoofs,  Strength  and  Cost  of.  248 

Field  Rivets,  Cost  of 424 

Avoidance   of 457 

Files   of   Drawings 435 

Filing   Drawings 467 

Financing  Manufacturing- 
Enterprises    8 

Fink  Trusses 121, 122,  125 

Fire  Curtains  in   Trusses 126 

Fire  Extinction .  19 

Fire  in  Car  Barns 21,  22 

Fire  in  Shops 19 

Fireproof   Buildings 473 

When    Needed 21 

Fire    Regulations   in   Wooden 

Buildings   157 

Flashing,  Chimney  and  Wall..  297 

Hip    and    VaUey 296' 

Metal    " '...  294 

of  Tin  Roofs 292 

Flat   Seam   Tin    Roofing 291 

Flat  Bars,  Not  Suitable  in 

Trusses 457 

Flintkote   Roofing 269 

Floor  Anchorage  for  Machines  221 

Floors,  Area  of 19 

Asphalt   217,  225 

Block    216 

Brick    217,  224 

Brick  Arch 236 

Cedar  Block  and  Cinder 219 

Cement  .                                    .  217 


PAGE 

Cement  Concrete 219 

Concrete,  To  Determine 

Thickness     237 

Corrugated    Iron 232 

Cost    of 61 

Different  Kinds  of 217 

Earth    217 

Framing    149 

Flat    Iron    Plate 231 

Loads    107 

Metal    Arch 232 

Multiplex   Steel   Plate, 

Weight    of 234 

Office  437 

Openings  in  Wood  Framing.  159 

Plank    217 

Safe    Load    on 240 

Preferably  Free  of  Parti- 
tions      30 

Reinforced    Concrete, 

Various  Kinds 236 

Slow  Burning  Timber 239 

Special    Kinds 230 

Steel  Beam  and  Wood  Joist.  238 

Tar  Concrete 217,  222 

Triangular    Trough,    Weight 

of    233,  236 

Upper 217,  231 

Wearing  Surface  on 238,  241 

Wooden 217,  227 

Wood   Block 230 

Foot    Bridges 375 

Foot  Walk  in  Gutters 192 

Footings,  under  Columns 199 

Spread    199 

Foreign  Languages, 

Quotations  in 477 

Forge  Shop  Walls 35 

Form  of  Buildings  Suited  to 

Contents ". 13 

Forms  for  Concrete 169 

Foundry  Buildings,  Cost  of...  39 

Foundation  Details 195 

Foundations,  Difficult  Ones...  195 

Settlement  of 197 

Timber  under  Machines.  .  . .  199 

Freight  Charges  on  Car  Loads  459 

Cost    of 423 

Framing,  Nature  of 20 

in  Wood,  Steel  or  Concrete.  .  20 

Strength  of 19 

Steel    119 

Furniture.  Arrangement  of  in 

Office     437 

Gables    146 

Gable  Cornices 294 

Purlins   459 

Galleries,   When   Suitable 23 

Galvanized   Metal,    When 

Preferable   475 


INDEX 


485 


PAGE 

Corrugated    Iron 274 

Gas  in  Shops 19 

Genasco's    Eoofing 270 

General  Features  and 

Eequirements    1 

German  Plant,  Plan  of 6 

Girders,    Weight    of 105 

in  Walls  407 

Girths  133 

Glass,  Best  Kind  for  Walls ...     80 

Panels   in   Doors 361 

Quality    of 316 

Eough,  and  Bough  Wire 316 

Eibbed,  and  Eibbed  Wire ...   316 

Tile  Skylights    319 

Walls,  Glare  of  Light  from.      79 
White,  Preferable  to  Green.    193 

Weight  and  Cost  of 317 

Glazing,   Cost  of 335 

Double    318 

Grading  of  Lot 10 

Granite  Eoofing 270 

Specifications    270 

Graphic    Statics,    Not 

Included Preface 

Graphite    Paint 385 

Gravel  in  Foundations 196 

Grillage    Beams 199 

Ground   Floors 218 

Ground  Space  Eequired  for 

Buildings    5,       7 

Growth  of  Old  Plants 1 

Gusset  Plates,  Detailing  of...    126 

Gutters,   Box 303,  304 

Combination 303,  304 

Drainage    of 78 

Hanging,   Cost   of 301 

Inside,  Objection  to 77 

on  North  Light  Eoofs 181 

Pitches : 77 

Eoof    303,  304 

Size   of    299,  302 

Slope  of 299,  302 

Supports    for 301,  302 

Valley    303,  304 

Hand  Cranes,  Loads  from .    115 

Handling  Appliances 19 

Heating    19 

Heating  of   Office 443 

Height  of  Clearances 14 

Height   of   Buildings,   Effect 

on  Cost 23,     29 

Hip   Flashing 290 

Homes  for  Employees 8 

Houses  for  Workmen 54,     55 

Impact,   Effect  of 115 

Ink,  Use  of  Eed  on  Drawings.   460 

Insurance  on  Buildings 474 

Insurance    Charges 169 


PAGE 
Interior  Columns,  One  or 

Two  Lines  of 120 

Interior  Light,  Effect  of 

Painting  on 81 

Iron,  Miscellaneous,  Cost  of.  ..  428 

Iron  Oxide  380 

Jack    Eaf ters 135 

Japans    382 

Jib  Cranes 137,  141 

Jib   Cranes,  Mast   Supports 

for 130,  139 

Joint  Plates,   Symmetrical....   459 

Kalsomine    388 

Knee  Braces 154 

Labor  Cost,  Effected  by 

Building  Design 27 

Market    5,     10 

Subdivision    of 448,  449 

Land,  Cost  of 23,     29 

Value  of 5,       8 

Lathing,  Cost  of . 429 

Lavatories  in  Office 443 

Laying  Out  Drawings 456 

Lead-Coated  Corrugated  Iron.  .   275 

Length  of  Stock 456 

Letters  on  Drawings,  Size  of .  .   462 

Lettering   Drawings 460 

Library  in  Office 434 

Lighting     19,23,     31 

Artificial    442 

Area    Eequired 81,     82 

General 79 

From  Eoof 79,     82 

From   Walls 79,  80,     82 

Of  Offices 441 

Of  Warehouses 79 

Lime,  Weight  of 205 

Linseed  Oil 378 

Lintels  in  Walls 407 

Lists,  Copying  of 466 

Listing  Items  on  Estimates....    413 

Listing  Material 465 

Loading,  Assumed 404 

Loads,  Crane 1 14,  115 

Floor,  According  to  Build- 
ing Laws 107 

Miscellaneous    116 

Provision  for  Increase  of .  .  .      95 

Snow  and  Wind 1 10,  111 

Slate  Eoof 95 

Summary  of 116 

Location   and    Site 5 

City  or  Suburban 8 

Lockers  for  Clothes 19 

Loose  Leaf  Books,  for  Office 

Eecords   440,  453 

Louvres,  Fixed 313 

Movable    ^.  .  .311,  314 

Use     of 47,48,     49 


486 


INDEX 


PAGE 

Machine  Anchors  in  Floor.  . .  .   221 

Machine   Drawings 448 

Foundations    199 

Shop  Floors,  Best  Kind 217 

Shops,   Cost   of 42,     44 

Machines,  Proper  Method   of 

Locating    12 

Bemoval  of  Large  Ones 19 

Machinery,    Arrangement 12 

Foundations    199 

Location  of 13 

Market  Buildings.  .47,  48,  49,  50,  51 

Stalls   47,48,     49 

Marking  Drawings 463 

Pieces  for  Export 478 

Masonry,   Cost  of 427 

Plan    456 

Weight  of 108 

Materials,  Cost  of 418,  427 

Ordering  of 454,  455 

Preservation  of 389 

Weight  of 108 

Mechanics '   Wages 420 

Mechanical  Engineer, 

Assistance  of 12 

Merchandise,  Weight  of 108 

Metal    Cornices 294 

Eeinforcement    169 

Shingles   289 

Metal  Ventilators,  Weight 

and  Cost  of 308,  309 

Metric  System,  When  Used...     39 

Mexico    Market 49,     50 

Mill  Building  Construc- 
tion  (1900)    Preface 

Mill  Buildings,  What  Included     12 

Mill  Construction,  Cost  of 27 

Mill  Scale,  Removal  of 390 

Mill  Wood  Work,  Cost  of .   428 

Moment  of  Inertia  of  Corru- 
gated   Iron 277 

Monarch    Roofing 271 

Monitor  Frames,   Outlines 

for    132,  133 

Monitors  for  Lighting.  .80,  83,     85 

on  Power  Houses 133 

Monitor  Windows 346 

Angle  with  Vertical 86' 

Leakage  of 191 

Monolithic  or  Separately 

Moulded    Members 169 

Mortar    205 

Motors,  Weight  of 116 

Movable  Wall  Panels 93 

Mules,    Transportation    on....   479 
Multiplex  Steel  Plate  Floors..   234 

Noise  in  Shops 19 

Northern  Light  Roofs 86 

Advantages  of 179 

Column    Spacing    for 182 


PAGE 

Cost  of 194 

Method    of    Framing 184 

Objection  to 179 

Outlines     of 180 

Window  Area  on 180 

Windows  for 193 

Ocean  Freight,  What 

Based  Upon 475,  477 

Office   Arrangement 431,  436 

Buildings  at  Shops 52 

Buildings,    Weight    of    Metal 

in  High 411 

Floor   Plans 432,  434,  441 

Furniture    403 

For  Shops 19 

Location    of 431 

Methods   404 

Organization 404 

Oil,    Linseed 379 

Quality  of 397 

Oiling   Steel   Work 394 

Old  Buildings,  Inefficient 1 

Operating  Mechanism  for 

Windows    355 

Ordering    Material 452 

Order    Office 440 

Schedule     455 

Ore  Bins, 46 

Ore   Pockets 45 

Weight  of  Steel  in 412 

Organization  of  Office 403 

Drafting    Room 444 

Ornamental  Iron,   Cost   of 428 

Paint 377 

Applying 392,  399 

Asphalt 384 

Carbonizing    Coating 385 

Coal    Tar 384 

Cold  Water 387 

Color    of 381,  392 

Comparative    Merits    of 

Different  Kinds 386 

Data   Table  of 394 

Driers  for 381 

Durable    Metal    Coating 384 

.  For  Brick  or  Cement  Walls.  387 

For  Woodwork 386 

Graphite     385 

Japans 382 

Merits  of 386 

Mixing  of 392 

Oil  for 379 

P.  &  B 384 

Pigments    for 379 

Prince  'a    Metallic 383 

Quality  of 397 

Solvents   for 381 

Stainers    for 381 

Vehicles   for. .  .  377 


INDEX 


487 


PAGl, 

Painting     389 

Air  Blast 393 

Cleaning    Before 390 

Cost   of 395,  429 

Pickling    Before 390 

Preservation    by 389 

Shop    Coats 394,  398 

Shop  Interiors 81 

Specifications    397 

Surfaces  in  Contact 398 

Tin    Eoofing 292 

Panels,  Length  of  Truss..  126,  127 

Paper,  Drawing 439 

Partitions,   Materials  for 162 

Absence  of  in  Shops 30 

in  Office 439 

Pencoyd   Shop   Floor 228 

Permanent  Buildings 20 

Photo  Developing  Koom 435 

Photo   Eeproduction   of 

Drawings    468 

Photography  in  Office 435 

Pickling  before  Painting 390 

Piers 195 

Pier  Caps,  Stone  or  Concrete..    197 

Pier  Shed  Columns 146 

Pigments  for  Paint 379 

Graphite     379 

Iron    Oxide 379 

Eed    Lead 379 

White    Lead 379 

Zinc  White 379 

Pilasters    34,  146 

Piles,  Safe  Load  on 200 

Wood  or  Concrete 199 

Piling,  Cost  of 427 

Pin  Plates 459 

Pins,  Ordering 456 

Pins    Use  of  in  Europe 473 

Pipe    Columns 143,  183 

Pitch    of    Roofs 71,     72 

Plank  Walls 213 

Safe  Load  on 240 

Eoofs,  Double  Thickness 243 

Plants,   Cost  of 29 

Plastering,    Cost    of 429 

Plates,  Maximum  Length  of..   455 

Plumbing,  Cost  of 429 

Plumbing  in  Office 443 

Portable    Dwellings 54,     55 

Power,    Supply    of 5 

Preliminary  Sketches 454 

Prepared  Eoofing 72,  268 

Preservation   of   Materials.  .  .  .    389 
Prices,  Approximate,  for  Esti- 
mating       427 

Price  Lists  of  Structural  Work  472 

Prince's   Metallic  Paint 383 

Printing  Machine 435 

Printing  Press  in  Office 461 

Prism    Glass 80 


PAGE 

Skylights  319 

Protection  of  Contents 19 

Purchasers,  Information   for.  .   476 

Directions   to 479 

Purlins   134 

Purlin  Anchors 135,  216 

Purlin   Fascia 459 

Purlins  at  Eave 133 

Fastening  of 458 

Location    of 457 

Spacing    for    Corrugated 

Asbestos 262 

Spacing  for  Corrugated 

Iron    133,  279 

Trussed   134 

Weight  of 131 

Purpose  and  Arrangements...     12 

Quotations   at    Seaboard 476 

Eadial  Plan  for  Shop  Arrange- 
ment     2,       3 

Eafter  Panels,  Length  of 126 

Eaf ters,  Best  Form  of 129 

Bailing,    Weight    of 412 

Eaw  Materials,  Proximity  of.       5 

Eeady  Eoofing 269 

Eecord    Eoom 435,  437 

Eecords,  Storage  of 435 

Eed    Lead 380 

Seduction  Process  in  Design...   480 
Eeinforced  Concrete  Buildings, 

Cost   of 43,62,     66 

Cost  of,  Per  Cubic  Foot 175 

Walls  35,  208 

Eeinforced    Bars 169 

Eelative  Value  of  Land  and 

Buildings   29 

Eesidence  of  Mill  Owners....       5 
Eibbed  Glass,  Where  Suitable.     80 

Eidges,  One  or  More 42,     47 

Eidge    Eoll 296 

Eight  and  Left  Pieces 462 

Eiveting,   Cost  of 424 

Eivets,  Location  of 454 

Size  of 458 

Staggering  of 458 

Stitch   459 

Values    of 457 

Eod    Bracing 152 

Eolling  Shutters,  Use  of 50 

Eoofs,  Non- Waterproof 242 

Moulded    Concrete    Slab 244 

Eeinforced  Concrete 244 

Total   Weight   of,   With 

Covering    106 

Eoof   Coverings 69 

Comparative  Merits  of 72 

Weight  of 105 

Framing,  Weight 

of    96,97,98,99,  100 


488 


INDEX 


PAGE 

Gutters 303 

Inclination  for  Tin  Roofing.  291 

Loads,   Static 95 

Outlines 74,  75,  76 

Pitches  Required  for 

Different    Coverings 72 

Pitches,  Diagram  of 71 

Plank,  Unsupported  Length 

of 242 

Slabs,   Monolithic    Concrete.  245 

Trusses,  Weight  of 410 

Ventilation    90 

Windows,   Vertical  or 

Sloping    184,  185 

Roofing,    Asbestos 268 

Asphalt     268 

Composition    266 

Carey's 268 

Cost  of 429 

Elaterite    268 

Flintkote    268 

Genasco's     268 

Granite     268 

Lytho;d    268 

Maltgoid    268 

Monarch     268 

Paracote     268 

Paroid    268 

Ruberoid    268 

Sheet  Metal 286 

Slag    26'8 

Tiles,   Weight   of 254 

V.    Crimped    286 

Round  House  Roof 245 

Round    House    Floor 218 

Round  House  of  Reinforced 

Concrete 178 

Rubber  Roofing 271 

Ruberoid    Roofing 272 

Sag  Rods 459 

Sand  for  Mortar 205 

Sand  Blast   Cleaning 391 

Sash,  Table  of 333 

Continuous 335 

Steel    343 

Wooden    333 

Saw    Tooth    Ventilation 90 

Scales   for   Drawings 454 

Scruppers     162 

Sessions  Foundry  Floor 224 

Shafting    Supports 142 

Sheathing  Boards  under   Tin 

Roofing     291 

Sheathing  on  Monitors 346 

Sheathing  Paper  under   Tin 

Roofing     291 

Sheet  Metal  Work,  Cost  of 427 

Roofing,  Method  of  Laying.  286 

Walls    213 

Weight  of  Flat  Sheets 286 


PAGE 

Shingles,   Metal 289 

Wood    264 

Shipping    Dimensions, 

Maximum 156 

Facilities    3,4,  7 

Lists    464 

Loose  Parts    459 

Marks 463 

Sizes,    Maximum 457 

Shop  Drawings,  Cost  of 469 

Shop  Work,  Cost  of 419,  422 

Show  Drawings 408 

Shutters  in  Walls 93 

on  Monitors 314,  346 

Sheet  Steel 342 

Steel  Rolling 371,  373 

Side  Wall  Foundations 198 

Side   Trusses,   Loads  from.  . .  .  125 

Simplicity  of  Design 19 

Site   10 

Size  of  Building 19 

Size  of  Products  and 

Machinery    23,  24 

Sketches,  Preliminary 452 

Skylights   319 

Area  Required  for 82 

on  Ridge,  Increased  Pitch  of  83 

Bars    320 

Box,  as  Ventilator 92 

Box   327 

Breakage  of 319 

Cost  of  Flat 326 

Flat     83 

Glass 317 

Glass  in  Plane  of  Roof 319 

Glass  Tile 319 

Hipped   327 

Individual    Box 319 

Over  Drafting  Office 441 

Prism    319 

Tile   329 

Translucent  Fabric 319,  330 

First  Use  of 330 

Slate,  Disadvantages  of 260 

Durability  of 260 

Fastening  to  Steel  Purlins..  259 
Method   of  Laying  and 

Fastening    258 

Punching  of 261 

Roofs,  Cost  of 261 

Roofing,  Required  Pitch  for.  257 

Roofing     255 

Size  and  Thickness 256 

Weight  of 257 

Slope  of  Roofs .70,  71,  72 

Slow    Burning    Construction, 

Cost  of 61 

Smoke  in  Shops 19 

Snow   Loads 110,  111 

Snow,  Roof  Slope  to  Expel  . .  110 

Soils,    Bearing   Power   of 196 


INDEX 


489 


PAGE 

Solvents  381 

Space  within  Buildings  for 

Contents 19 

Spacing  of  Trusses 131 

Specifications   for  Painting...  397 

Sprinkling    Systems 164 

Squad  Foremen,  Duties  of....  452 

Squad   Systems 448 

Stainers,  for  Paint 381 

Stair    Towers 159 

Stairways    159 

Stairs,  Weight  of 412 

Stairs  in  Office,  Location  of..  440 

Standard  Details 405 

Standing  Seam  Corrugated 

Iron     282 

Standing  Seam  Tin  Eoofing.  . .  292 

Static   Roof  Loads 95 

Stationery,    Office 452 

Steamboat  Ventilators 310 

Steel  Buildings,   Comparative 

Cost   of 58,     G2 

Exporting    of 473 

Steel  Frames,  Weight  of 410 

Steel   Roll   Roofing 287 

Steel  Shapes,  Cost  of  at  Mills  419 

Steel   Troughs,  Floor 231 

Stiff  Members,  Preference  for.  125 

Stock,  Length   to  Order 456 

Ordering    of 454 

Stone  Pier   Caps 198 

Stone  Walls,  Cost  of 204 

Storage   Yards 7 

Storing  of  Goods,  Space  for..  19 

Stories,  Number  of 23,     29 

Stresses,   Computations   of....  404 

Useless  Refinement  in 

Computing 404 

Stress  Sheets,  Checking  of 452 

Strength  of  Buildings 19 

Structural  Steel,  Cost  of 428 

Strut  Braces 153 

Stucco    Walls 475 

Sturtevant  Plant 2 

Floor  in 224 

Subways  for  Buildings 2 

Suburban    Offices 431,  433 

Suburban  Plants 8 

Sub-Bids,   Securing  of 416 

Sugar  House,  Cost  of 45 

Suggestions  to  Purchasers 476 

Summary   Sheets 415 

Sun  Shades  on  Tropical 

Buildings   474 

Supply   Room 437 

Superintendent's    Office... 440,  450 

Survey  of  Site 11 

Symmetrical    Plates 458 

Tables,    Drafting 436,  437,  438 

Tar  Concrete  Floors 222 

Tar  and  Gravel  Roofing, 


PAGE 

Pitch  for 267 

Specifications    for 266 

Telephone  Systems 440 

Templets,  Cost  of 422 

Temporarv  Buildings,  When 

Desirable   20 

Tenders    425 

Tenders,  Invitations  for 402 

Form  of 425 

Terne  Plates 290 

Thatched  Roofs 475 

Theory  of  Economic  Design..        1 

Tiles,  Glass 253 

Interlocking    253 

Unglazed    253 

Federal     255 

Ludowici,  Cost  of 254 

Tile,  Reinforced  Concrete 255 

Roofing,    Surface    beneath..   253 

Skylight     330 

Tin  Clad  Doors 362 

Title    of    Drawings 460,  461 

Tin  and  Terne  Plate  Roofing..   289 

Title  of  Drawings 460,  461 

Toilets    19 

Tracing  Cloth 460,  462 

Tracing    Drawings 453,  462 

Transfer  of  Goods  in  Shops, 

Cost    of 30 

Translucent  Fabric  Skylight..   319 
Trautwine,    The    Engineers' 

Authority    404 

Travel,  Avoidance  of  Useless. .     19 
Traveling  Cranes,   Space 

for    23,     24 

Trolleys    136 

Trolley  Beams 114 

Trolley   Connections   to 

Suburban  Plants 10 

Tropical    Buildings, 

Features  of 474 

Trough  Floors,  Weight  of 231 

Truss  Anchors 216 

Truss  Connections,  Pins  or 

Rivets    126,  128 

Depth    128 

Forms,   Right  and   Wrong 

Outlines    127 

Members,   Stiff  Pieces 

Preferable     125 

Outlines    120  to     125 

Spacing    131 

Systems,  Single  or  Double..    126 

Weights,  Charts  for 97  to  105 

Trusses,    Required    Stiffness 

for   Loading 127 

Weight    of 96  to  102 

Trussit  Metal 247 

Tunnels    Between    Buildings..        2 

Turnbackles    152 

Turpentine,   Spirits   of 381,  392 


490 


INDEX 


PAGE 

Upper   Floors 231 

Utility,  a  Prime  Eequisite 19 

Valley    Flashing 296 

Gutters 304 

on  Tin  Roofs 292 

Varnishes    382 

Vehicles  for  Paint 377 

Ventilating     19 

of  Offices   443 

Methods    of 88 

Ventilation    Area 89 

By  Blower  System 88 

By    Continuous    Roof 

Openings    91 

By  Forced  Drafts 308 

By   Individual   Metal 

Ventilators    308 

By  Movable  Wall  Panels.  .  .  92 

By  Wall  Flues 92 

Shutters     314 

Through  Wall  Openings 308 

Through  Continuous  Roof 

Openings    308 

Through    Saw    Tooth 

Windows    308 

Through    Monitors 308 

Methods  of 90 

Of  Markets 50,  51,  52 

Of  North  Light  Roofs 190 

Ventilators    308 

Box   Skylight 92 

Individual  Metal 91 

Steamboat   91 

Vessels,    Maximum    Sizes 

Accepted    by 478 

Vibration   in  Buildings, 

Prevention    of 34 

Wall  Anchorages 214 

Bolts  215 

Boxes  for  Floor  Beams.  .  .  .  164 

Details  203 

Flashings  297 

Girders 407 

Panels,  Movable  on  Forge 

Shops  35 

Thickness,  Suited  to  Column  34 
Walls,  Choice  of,  Effected  by 

Need  of  Heating 20 

Color  of,  in  Office 441 

Combined  Brick  and 

Concrete 208 

Concrete  Block 212 

Cost  of  Per  Square  Foot 36 

Effect  of  Color  on  Light 81 

Expanded  Metal  and 

Concrete 44 


PAGE 

Hollow  Concrete 212 

Kind  to  Use 407 

Material    in 32 

Reinforced  Concrete 208,  209 

Sheet   Metal 212 

Stucco    475 

Thickness  of   32,33,  204 

Various  Kinds 20 

With  Movable  Panels 92 

Wooden,    Cost    of 213 

Wages,  Table  of 420 

Warehouse,   Cost   of 44 

Weight   of   Steel   in 411 

Wash  Rooms 19 

Weatherboard  Walls 37 

Wearing  Surface  of  Floors...   238 
Weight   of   Building  Materials  108 

Curves,  for  Estimating 405 

of  Machinery  on  Floor 28 

of  Products 23,     24 

of  Roof  Framing 96  to  100 

of  Trusses,  Formula  for.  132,  410 
Welfare  Features  at  Plants. 4,  433 

White    Lead 379 

Whitewash    388 

Wind  Loads Ill,  112 

Windows,  Cost  of 428,  340 

Metal  Sash 340 

Monitor    346 

Movable 338 

Northern    Light    Roofs 193 

Protection    from    Fire 162 

Provision  for  Cleaning 88 

Side    Wall 333 

Various  Forms 80 

Window  Area  Required, 

Rule  for 82 

on  North  Light  Roofs 180 

Casing    298 

Frames    335 

Frames,  Monitor 346 

Opening    Mechanism 355 

Opening   Appliances.  .  190   to  193 

Wood  Block  Floor 230 

Buildings,    Comparative 

Cost   of 58,62,     66 

Floors   227 

Floors,  Cost  of 229,  241 

Framing 157 

Mill   Construction 63 

Roofs    242 

and  Steel  Framing,   Cost 

Compared     64 

Shingles   264 

Walls    214 

Woods,  Weight  of 108 

Zinc   Oxide..  ...  380 


THIS  BOOB 


AN  INIT 

WILL  BE  AS 
THIS   BOOK 
WILL INCRE 
DAY    AND    1 
OVERDUE. 


ac 


&<&,    II        8/97 

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OCT_JJ 


23Apr'5lwj 


NRLF/ACCESS 
20,000 


13Apr54V  6 


£ 


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